for those who bought Radionlink R9DS for Navio2 projects - dont panic yet.
My Radiolink R9DS produced within recent months worked perfectly fine with Navio 2 using SBUS. I will share project details in separate thread soon.
I did not have to do any tricking or workarounds configuration, it just worked fine!
So hopefully for other people it may work as well.
So far I am happy with this transmitter.