After editing the config file, you should stop and restart AudioStreamer.exe for the changes to have effect.
You can change the port from 9090 to 9091, but after changing this in the config file you have to stop and start AudioStreamer.exe
Remark: It is not possible to have 2 instances of AudioStreamer.exe on the same port.
It’s possible to have 2 instances running, but you have to use another port and you have to create/copy a whole new AudioStreamer folder.
Hope this helps…