I had this problem too. Not because I wanted the charger to turn max rpm at the same time as the engine was max 9000rpm, but because I decided that I wanted to max out at 8-9psi.
The charger pulley was already max diameter to fit the belt cover, so I use a smaller crank pulley. Had it custom made from my CAD drawing. Ended up with 9psi, so my calculations for pulley diameter vs the charger map were not bad.
