Sorry to hear you are having connection issues. I am able to connect to my H9 on my computer running Monterey. Are you using the latest H9 Firmware and H9 Control software?
If you are having issues with the latest versions of the software and firmware, can you resetting all settings in H9 Control? This can be done be going to: Settings -> Reset Settings -> Reset All Settings. You will need to login to enter your Eventide username in H9 Control after doing this.
I was able to connect to my MacBook Pro (monterey 12.0.1) with no issues.
When you connect to your H9 via Bluetooth, please make sure to leave MIDI and USB ports unconnected.
Also, did you make the Bluetooth connection in Mac’s system setting? Can you try connecting to your H9 just in the app by clicking “Manually select a device” -> “Connect via Bluetooth” -> select your H9 and click “Browse” ?