Are you powering the Push from the hub? The Push pulls a LOT of power and can have reset issues with too many other devices on the hub. I’ve had that problem with the Push and unpowered hubs or under-powered hubs too and other devices.
The plugin will initially connect to the first MIDI device it sees, but it sends no data initially, so there shouldn’t be any interaction even if it were to connect to the Push (and that wouldn’t be dependent on where the devices were plugged anyway). Since the plugin only talks MIDI it doesn’t care about USB or other devices directly and can have no effect on them.
So I would suggest considering the power draw on the Push and maybe trying to power it from an external supply when using that hub? Also consider that the H9 is a VERY chatty pedal when you’re using the H9 control and that much traffic may be overwhelming the USB bus to the hub, if the hub is as busy as you say.
Eventide does not recommend running H9 control at the same time as other MIDI controllers are communicating with the pedal, but I’ve had very little issues (other than H9 control getting confused and out of sync sometimes) with doing so. But that might be another avenue to look after, as well.