I really think the problem is not the H9…

I would suggest a few things:

Try setting 2 switches on the GCP to send different values (0-127) for the same CC you've set for expression on the H9. Then push one switch at a time on the GCP and see if the H9 respond… If the H9 respond then something else is wrong in your setup.

Or better: Use a midi software (midi-ox on PC) to see if the GCP is in fact transmitting the correct value.

(Auto calibration has nothing to do with this)

LA