Well, do you want your G systems to send MIDI clock to the H9, or do you want it to trigger the Tap Tempo pedal function on the H9?  If you want it to do the latter, you'll need to configure your G systems to send a MIDI CC when one of its switches is pressed, and you'll need to configure the H9 to connect this MIDI CC to tap tempo.  You can do this in H9 Control by clicking on the Pedal button in the bottom menubar, going to MIDI Settings, going to 'Assign MIDI CC messages to pedal functions,' and then to the 'Tap Tempo' pedal function.