I have these boards plugged together in a stack. Without the audio board in the stack, I can get the color display to work with the example sketches using pins 9 and 10 as DC and CS. When I put the audio board in the stack, even modifying the defines to pins 20 and 21 per the web page, all I get is a flickering white screen. Here's an example sketch that works without the audio board:

/************************************************** *
This is our GFX example for the Adafruit ILI9341 Breakout and Shield
----> http://www.adafruit.com/products/1651

Check out the links above for our tutorials and wiring diagrams
These displays use SPI to communicate, 4 or 5 pins are required to
interface (RST is optional)
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.
MIT license, all text above must be included in any redistribution
************************************************** **/


#include "SPI.h"
#include "ILI9341_t3.h"

// For the Adafruit shield, these are the default.
#define TFT_DC 20 //Note: pin 9 without audio board works
#define TFT_CS 21 // Note: pin 10 without audio board works

// Use hardware SPI (on Uno, #13, #12, #11) and the above for CS/DC
ILI9341_t3 tft = ILI9341_t3(TFT_CS, TFT_DC);

void setup() {
tft.begin();
tft.fillScreen(ILI9341_BLACK);
tft.setTextColor(ILI9341_YELLOW);
tft.setTextSize(2);
tft.println("Waiting for Arduino Serial Monitor...");

Serial.begin(9600);
//while (!Serial) ; // wait for Arduino Serial Monitor
Serial.println("ILI9341 Test!");

// read diagnostics (optional but can help debug problems)
uint8_t x = tft.readcommand8(ILI9341_RDMODE);
Serial.print("Display Power Mode: 0x"); Serial.println(x, HEX);
x = tft.readcommand8(ILI9341_RDMADCTL);
Serial.print("MADCTL Mode: 0x"); Serial.println(x, HEX);
x = tft.readcommand8(ILI9341_RDPIXFMT);
Serial.print("Pixel Format: 0x"); Serial.println(x, HEX);
x = tft.readcommand8(ILI9341_RDIMGFMT);
Serial.print("Image Format: 0x"); Serial.println(x, HEX);
x = tft.readcommand8(ILI9341_RDSELFDIAG);
Serial.print("Self Diagnostic: 0x"); Serial.println(x, HEX);

Serial.println(F("Benchmark Time (microseconds)"));

Serial.print(F("Screen fill "));
Serial.println(testFillScreen());
delay(200);

Serial.print(F("Text "));
Serial.println(testText());
delay(600);

Serial.print(F("Lines "));
Serial.println(testLines(ILI9341_CYAN));
delay(200);

Serial.print(F("Horiz/Vert Lines "));
Serial.println(testFastLines(ILI9341_RED, ILI9341_BLUE));
delay(200);

Serial.print(F("Rectangles (outline) "));
Serial.println(testRects(ILI9341_GREEN));
delay(200);

Serial.print(F("Rectangles (filled) "));
Serial.println(testFilledRects(ILI9341_YELLOW, ILI9341_MAGENTA));
delay(200);

Serial.print(F("Circles (filled) "));
Serial.println(testFilledCircles(10, ILI9341_MAGENTA));

Serial.print(F("Circles (outline) "));
Serial.println(testCircles(10, ILI9341_WHITE));
delay(200);

Serial.print(F("Triangles (outline) "));
Serial.println(testTriangles());
delay(200);

Serial.print(F("Triangles (filled) "));
Serial.println(testFilledTriangles());
delay(200);

Serial.print(F("Rounded rects (outline) "));
Serial.println(testRoundRects());
delay(200);

Serial.print(F("Rounded rects (filled) "));
Serial.println(testFilledRoundRects());
delay(200);

Serial.println(F("Done!"));

}


void loop(void) {
for(uint8_t rotation=0; rotation<4; rotation++) {
tft.setRotation(rotation);
testText();
delay(1000);
}
}

unsigned long testFillScreen() {
unsigned long start = micros();
tft.fillScreen(ILI9341_BLACK);
tft.fillScreen(ILI9341_RED);
tft.fillScreen(ILI9341_GREEN);
tft.fillScreen(ILI9341_BLUE);
tft.fillScreen(ILI9341_BLACK);
return micros() - start;
}

unsigned long testText() {
tft.fillScreen(ILI9341_BLACK);
unsigned long start = micros();
tft.setCursor(0, 0);
tft.setTextColor(ILI9341_WHITE); tft.setTextSize(1);
tft.println("Hello World!");
tft.setTextColor(ILI9341_YELLOW); tft.setTextSize(2);
tft.println(1234.56);
tft.setTextColor(ILI9341_RED); tft.setTextSize(3);
tft.println(0xDEADBEEF, HEX);
tft.println();
tft.setTextColor(ILI9341_GREEN);
tft.setTextSize(5);
tft.println("GROOP");
tft.setTextSize(2);
tft.println("I implore thee,");
tft.setTextSize(1);
tft.println("my foonting turlingdromes.");
tft.println("And hooptiously drangle me");
tft.println("with crinkly bindlewurdles,");
tft.println("Or I will rend thee");
tft.println("in the gobberwarts");
tft.println("with my blurglecruncheon,");
tft.println("see if I don't!");
return micros() - start;
}

unsigned long testLines(uint16_t color) {
unsigned long start, t;
int x1, y1, x2, y2,
w = tft.width(),
h = tft.height();

tft.fillScreen(ILI9341_BLACK);

x1 = y1 = 0;
y2 = h - 1;
start = micros();
for(x2=0; x2<w; x2+=6) tft.drawLine(x1, y1, x2, y2, color);
x2 = w - 1;
for(y2=0; y2<h; y2+=6) tft.drawLine(x1, y1, x2, y2, color);
t = micros() - start; // fillScreen doesn't count against timing

tft.fillScreen(ILI9341_BLACK);

x1 = w - 1;
y1 = 0;
y2 = h - 1;
start = micros();
for(x2=0; x2<w; x2+=6) tft.drawLine(x1, y1, x2, y2, color);
x2 = 0;
for(y2=0; y2<h; y2+=6) tft.drawLine(x1, y1, x2, y2, color);
t += micros() - start;

tft.fillScreen(ILI9341_BLACK);

x1 = 0;
y1 = h - 1;
y2 = 0;
start = micros();
for(x2=0; x2<w; x2+=6) tft.drawLine(x1, y1, x2, y2, color);
x2 = w - 1;
for(y2=0; y2<h; y2+=6) tft.drawLine(x1, y1, x2, y2, color);
t += micros() - start;

tft.fillScreen(ILI9341_BLACK);

x1 = w - 1;
y1 = h - 1;
y2 = 0;
start = micros();
for(x2=0; x2<w; x2+=6) tft.drawLine(x1, y1, x2, y2, color);
x2 = 0;
for(y2=0; y2<h; y2+=6) tft.drawLine(x1, y1, x2, y2, color);

return micros() - start;
}

unsigned long testFastLines(uint16_t color1, uint16_t color2) {
unsigned long start;
int x, y, w = tft.width(), h = tft.height();

tft.fillScreen(ILI9341_BLACK);
start = micros();
for(y=0; y<h; y+=5) tft.drawFastHLine(0, y, w, color1);
for(x=0; x<w; x+=5) tft.drawFastVLine(x, 0, h, color2);

return micros() - start;
}

unsigned long testRects(uint16_t color) {
unsigned long start;
int n, i, i2,
cx = tft.width() / 2,
cy = tft.height() / 2;

tft.fillScreen(ILI9341_BLACK);
n = min(tft.width(), tft.height());
start = micros();
for(i=2; i<n; i+=6) {
i2 = i / 2;
tft.drawRect(cx-i2, cy-i2, i, i, color);
}

return micros() - start;
}

unsigned long testFilledRects(uint16_t color1, uint16_t color2) {
unsigned long start, t = 0;
int n, i, i2,
cx = tft.width() / 2 - 1,
cy = tft.height() / 2 - 1;

tft.fillScreen(ILI9341_BLACK);
n = min(tft.width(), tft.height()) - 1;
for(i=n; i>0; i-=6) {
i2 = i / 2;
start = micros();
tft.fillRect(cx-i2, cy-i2, i, i, color1);
t += micros() - start;
// Outlines are not included in timing results
tft.drawRect(cx-i2, cy-i2, i, i, color2);
}

return t;
}

unsigned long testFilledCircles(uint8_t radius, uint16_t color) {
unsigned long start;
int x, y, w = tft.width(), h = tft.height(), r2 = radius * 2;

tft.fillScreen(ILI9341_BLACK);
start = micros();
for(x=radius; x<w; x+=r2) {
for(y=radius; y<h; y+=r2) {
tft.fillCircle(x, y, radius, color);
}
}

return micros() - start;
}

unsigned long testCircles(uint8_t radius, uint16_t color) {
unsigned long start;
int x, y, r2 = radius * 2,
w = tft.width() + radius,
h = tft.height() + radius;

// Screen is not cleared for this one -- this is
// intentional and does not affect the reported time.
start = micros();
for(x=0; x<w; x+=r2) {
for(y=0; y<h; y+=r2) {
tft.drawCircle(x, y, radius, color);
}
}

return micros() - start;
}

unsigned long testTriangles() {
unsigned long start;
int n, i, cx = tft.width() / 2 - 1,
cy = tft.height() / 2 - 1;

tft.fillScreen(ILI9341_BLACK);
n = min(cx, cy);
start = micros();
for(i=0; i<n; i+=5) {
tft.drawTriangle(
cx , cy - i, // peak
cx - i, cy + i, // bottom left
cx + i, cy + i, // bottom right
tft.color565(0, 0, i));
}

return micros() - start;
}

unsigned long testFilledTriangles() {
unsigned long start, t = 0;
int i, cx = tft.width() / 2 - 1,
cy = tft.height() / 2 - 1;

tft.fillScreen(ILI9341_BLACK);
start = micros();
for(i=min(cx,cy); i>10; i-=5) {
start = micros();
tft.fillTriangle(cx, cy - i, cx - i, cy + i, cx + i, cy + i,
tft.color565(0, i, i));
t += micros() - start;
tft.drawTriangle(cx, cy - i, cx - i, cy + i, cx + i, cy + i,
tft.color565(i, i, 0));
}

return t;
}

unsigned long testRoundRects() {
unsigned long start;
int w, i, i2,
cx = tft.width() / 2 - 1,
cy = tft.height() / 2 - 1;

tft.fillScreen(ILI9341_BLACK);
w = min(tft.width(), tft.height()) - 1;
start = micros();
for(i=0; i<w; i+=6) {
i2 = i / 2;
tft.drawRoundRect(cx-i2, cy-i2, i, i, i/8, tft.color565(i, 0, 0));
}

return micros() - start;
}

unsigned long testFilledRoundRects() {
unsigned long start;
int i, i2,
cx = tft.width() / 2 - 1,
cy = tft.height() / 2 - 1;

tft.fillScreen(ILI9341_BLACK);
start = micros();
for(i=min(tft.width(), tft.height()) - 1; i>20; i-=6) {
i2 = i / 2;
tft.fillRoundRect(cx-i2, cy-i2, i, i, i/8, tft.color565(0, i, 0));
}

return micros() - start;
}