I have a similar set-up and was able to set-up one of the instant access buttons on the Ground Control to turnon/off the H9 pedal. To do so, go to the Midi set-up on the H9 control app. There will be a lot of functions listed (don’t recall exactly where as I dont have the app with me). Go to Bypass and assign a CC value.Then, use that same CC value when setting up yor GC (i.e. 0, or 1). Make sure you’ve set-up your midi channel correctly on both GC and H9.
The only issue I am having with this is that the Instant access Ground Control light is on when the H9 is bypassed, and off when the H9 is on. Also, there are no delay/reverb trails.I think that issue was identified but yet to be addressed unless I’m mistaken.
Hope this helps, and hope some other users can assist with light issue on GCX as well as the delay trails issue.