I made a quick screencast showing how you can do this:
I'll quickly describe what I'm doing in the screencast. I connected two H9s to H9 Control, and I went to H9 Control's Preset screen. On the first H9, I used the big, black wheel on the H9 itself to call up the preset I want to copy; it's preset #3 on that H9 titled "My Awesome Preset". Loading it up on the H9 causes it to appear in H9 Control as well. I press save and save this preset locally to H9 Control. Then, I select the serial number of my 2nd H9 in the top bar to connect to the second H9. I navigate through my presets to find the preset I just saved, i.e. My Awesome Preset, and I save that preset to preset position 3 on the 2nd H9. Then, at the end I go into the Preset List screen and look at the contents of both H9s in the preset list screen to verify that "My Awesome Preset" is now saved at preset position 3 on both H9s.