it's hard to diagnose sound issues on a forum. when I read your post I'm not reading anything about not hearing the sound when the HVAC system is turned off.

also you say you hear the whine when driving and a HVAC blower issue should be apparent when the car is stopped. Of course air flow when moving could move debris into the path of the blower fan.

I just don't want to convey as a fact that it is your blower motor.

I hope you post some more information and let us know how things go so we can fix it.