Buying auto insurance. You have 3 license drivers in the family.
One is the owner of the vehicle, but doesn't drive that much.
Can a driver not the owner of the car buy the policy?

Sure. As long as all drivers are on the policy. Rates will be determined by the driver with the worst driving record and any who are under 25 (along with all the other things, like make and model and age of car, and where you live, garage or not, etc).