I'm not having the expected result when I follow the steps above and wonder if anyone can help me figure out what might be wrong. The receiving H9 does not adjust, i.e. speed. I know I have a working DIN5 cable between them because the receiving H9 can get messages from my MIDI foot controller. But in that case, my 1st H9 is set to MIDI/OUTPUT=THRU+MIDI CLOCK and the tap tempo is generated by the foot controller, sending a CC# to each H9's MIDI Channel. 

I'd like to be able to adjust both tap tempos from the iOS app but can't get the Control app Tap to adjust the tempo of the recieving H9. Is there anything else I should look at?

If it is relevant, the reciving MIDI Clock settings on the recieving H9 are: 

Enable MIDI Input Clock= NO (I've tried YES with no success)

Enable MIDI Clock Filter= NO

Enable MIDI Output Clock= NO

You need to turn on the first H9's MICI Clock output (CLK.OUT -> ON), and turn on the second H9's Clock input (CLK IN -> ON). Then you should set both H9 into tempo mode (TMP ON in BPM) by pressing the right footswitch and the PRESETS button. (You may do this more easily in H9 Control). Now tapping on the first H9 should send a MIDI clcok to the second H9 and the second H9's tempo should sync with the first one.