I have a device that I want to connect to the home automation.

The device communicates with its control unit via RS485 9 bit data (9N1) Baud 9600.
Its a Master / Slave communication. I need to simulate a slave answer the maser in about 30-50ms.

The communication with the home automation should work via a small web server with http query or later maybe via mqtt, I'm not sure yet.

I tried it with an ESP32 and software serial, but here I get quite often wrong values via the serial interface, probably timing errors.

I have seen that you can activate 9 bit hardware serial at a Teensy >3.
Would this work with a Teensy 4.1 with the internal Ethernet interface, RS485Max and a 3.3V/5V Logic Level Converter.
Is there a better board ?

What do you think ?