My kids went to preschool. 2 days a week (could've done 3 if I had the money), 9-3. It was privately owned (I think?), an off-shoot of a church, though it wasn't religious.
They are becoming less common though, as the demand for longer hours like daycare is high. Even my kids wonderful preschool has expanded now to have a 2yo room, and has the option of 830-330.
My kids loved their preschool though, much much better IME than daycare. I would highly recommend one if you can find one.