I just received a reply from Musicomlab so I'll post this here in case anyone else has a similar situation.
This is Hyungwoo Kim from Musicom Lab.
I think H9 tuner is activated regardless of CC value.
EFX transmit CC value 127 when FS1 is ON and CC value 0 when FS is OFF.
I'm sorry, I think there is no way that EFX can control the tuner of H9
I'd also be up for the hot knob to possibly control the tuner? If ther is any way that we can avoid having to step on two buttons at the same time. Thanks for the replies!
