Hm… We'll have to see if we can reproduce that. Hopefully, we won't need a Audio Interface Native Instruments Komplete Audio 6 to do so.
You mentioned that H9 Control is crashing even when it isn't connected through your MIDI interface if that MIDI interface is connected. I think you could get rid of that problem by erasing the setting that causes it to try to connect to your H9 through the MIDI interface. You can reset all the app settings by clicking on the Settings button in the bottom right hand corner of H9 Control and going to Reset Settings and using the reset all settings function. After you do this, when you restart H9 Control with your device connected (via USB), you're going to need to enter your user name and password again to verify your registration info, but hopefully after you do this, you'll be able to connect your devices via USB without it causing anything to crash.