Sorry if this has already been posted but I thought it would be cool if you connect several H9 units together via a "central brain" device via the midi in/out. With a central brain and a new app where you could designate each button on each H9 to a certain function (bank up/down, tap tempo, tuner select, etc.) This could potentially eliminate extra foot switches, midi controllers, etc while having all the units communicate with one another, both ways.
I have 3 H9 and with 6 buttons that would easily take care of my preset up/down, selection, tap temp, tuner select and an instant "looper mode" button. You could even make it a small box about the foot print of the H9 so that it sits underneath one of them and has recessed midi ports.