Sorry, H9 Control connection via MIDI is not designed to work like this. 2 H9s have to be paralel in the connection. Otherwise, MIDI messages will mess up H9 Control.
Again, Bluetooth should be the best solution. Have you tried your phone/tablet? Bluetooth on mobile devices behaves much better than Windows.
I also recommand you use USB cables to connect to your H9 for programming/editing/managing presets, and then use your MIDI controller without H9 Control when you play live.
