Are you saying that you don't hear this noise normally, like driving the car? Many cars make unusual drivetrain noises running (freewheeling) on a hoist with the wheels off the ground (no drivetrain, rolling resistance). You should hear all the strange sounds ALL AWD Volvos (or other AWD vehicles) make running them on a hoist, sound like everything's bad.
If you're not hearing anything normally, then you have nothing to worry about.
Un un-torqued hub (?) or axle spinning as you've mentioned will make noise, no doubt.

As for the vibration, despite what you say about balance, a high speed vibration is most likely due to improper wheel balance although I wouldn't rule out a bad tire (out of round which should be visable as you're watching it spin on a hoist) or slighly bent wheel (also obvious spinning off the ground).
Have you tryed rotating wheels front to back?

What tire rating do you have? T? H? Z?

I had the same kind of problem( Yokohama Avid T4). Tire shop was balancing, balancing, balancing....and always had the same answer that maybe I was crazy and that their balancing machine was perfect.... They gave me 2 new tires, no fix. They looked at the car and said that it would be fix by changing the left driveshaft because they could see a little move(up and down) on it.

Finally went to an indy volvo guy who as soon as he drove the car said that I din't had the right tire rating for this car. He explained me that the machine they use for balancing cant see that kind of problem because the rotating speed is too low to make that kind of "deformation".

The tire shop sold me T rated tire and nothing less than H should be installed on this car if you drive over 70 mph. It seems that those tires(T rated) were too soft so they were "deforming" at high speed.

Changed for H rated(Potenza RE 950)and now the car is going great.