I would say not the H9, for one, because I think you can see the signal light flashing on/off with the noise. That indicates to me something is getting in the signal path somewhere before the H9. Is this H9 wired PRE/POST, or stereo? What happens if you use true bypass?

I would go through the connections first and eliminate any obvious sources of ground loops (non-isolated power supplies, grounds, etc.) or noise and start process of elimination between the H9 and front of the amp.

Hard to say but sounds like a power supply, interference or grounding issue to me.