[Ari423]

I would say it's not 100% necessary but very much recommended. You are going to be putting a significant amount of sideloading on those CIM shafts. If they aren't supported, they will likely bend. Also, even with some load on the motor from the wheel, the CIM will be spinning at a significant percent of its free speed. That means it's spinning really fast (multiple thousand RPM). When the wheels come in contact with the ball a few times, it will likely shred the coating off the ball and the tread off the wheels. You may want to add a gearbox between the CIM and the flywheels to slow them down and give them more torque to push out the ball.