This might be naive, but have you tried a different cable?  IME Half the time that things work and then don't work, it's the cable at fault.  Can you confirm that the H9 can send other MIDI messages, such as a program change?  You should see the light on the Moog flash whenever it receives a MIDI message, so you can check your hardware that way without having to question whether the MIDI clock is operating as you expect.