Also, when using H9000 as a USB audio interface, does it also work as a computer to midi interface? Can I send midi data from software to the H9000 midi outputs, or would I just have to use the MIDI thru in that case?
Just to clarify a few things about using MIDI with the H9000:
The H9k does not output a MIDI clock signal from the MIDI DIN or USB ports. The H9k only outputs MIDI CC data, and it only does this when using the MIDI controller feedback feature. See this post for details about MIDI controller feedback: https://www.eventideaudio.com/community/forum/rackmount/h9000-13-production
So, currently you would not be able to use the H9k as a computer to MIDI interface, although there is a possibility that the H9k could be updated to be able to do this sometime in the future.
The MIDI thru on the H9k only mirrors what the MIDI DIN input receives, it does not mirror any MIDI information that is received from the USB inputs.