Couldn’t you just use dire wolf? It is a free soft Tnc that supports 9600
Direwolf is awesome..
I’m a huge fan of direwolf. Pair a usb soundcard with a cheap radio and you can easily have a ~$100 dollar aprs rigs that can tx and rx.
We still, even after all these years, have a real lack of a 'good' higher speed packet radio. The cheap (BaoFeng?) radios will work (sorta) for APRS but at slower speeds (maybe up to 3600?) and they have a TXD an order of a magnitude longer than acceptable.
There are some options for 9600 (or faster) but there are still issues and challenges.
I had to spend more than $100 total to do 9600 I'd question the whole
The problem with Packet Radio is still the 'radio.' A reasonable 9k6 station is about $250 - but at that price better off just getting an off the shelf Kenwood TH-D710 which works well at 9k6 and offers a second channel.
Adjusted for time - these are still way cheaper than the $500 I paid in 1986 for my first 1200 baud packet station consisting of a Kantronics KPC and Yeasu HT.
The article on 9600 packet in last years DCC proceedings (PDF is available on the web) is a good review of the technology and is a start for looking at radios.
73 Bill, WA7NWP