The H9 SysEx ID does currently not work.
(H9 Control Version 2.9.3, Stompbox software 5.4.1.7)
When I set a SysEx ID other than 1 on the H9, the H9 Control can no longer connect to the device.
This is not really bad at the moment because we cannot use SysEx anyway yet. But at the time we get the promised documentation, the ID may become important.