OK, sounds like good news.  What I understand you to say is effectively: go ahead and hook up MIDI with MIDI cables and use the control app.  If all you are doing is just program changes with another MIDI controller and a tweak now and then on the control app, things should work.  It’s a bandwidth limitation, just don’t do any giant data transfers in the middle of a song. 

Do I understand that correctly?

So does that mean program changes made with my 3rd party midi controller will be reflected in the H9 Control app?  I.e., it will show what preset is selected?  I don’t need it to go in the other direction; I just need the H9 to be a slave device that responds to MIDI program changes with its MIDI change map.