Spend you time getting good training and instruction.
As ASMI found out the findinds are inconclusive. Check out their web site. American Sports Medical Institute.
I was lucky I had good adivce right from 9-10yo when my son started pitching. The advice flew in the face of all the popular thinking My job was to make sure he threw properly and get him good advice. He threw CBs from 9-10yo and the worst thing that ever happened was a swollen Ulnar because of freezing cold weather and his team was at bat too long cooling down his arm. He as taught shut him self down feeling stifness in the elbow area after throwing a couple pitches in the 5th. Teaching your son to know his body is also a good way to help protect him. If they don't feel right shut it down.
We also have check ups by a sports/pitching Doctor who keeps a good eye on him. I actually got to the poit that I wondered wether he was bordering on paranoia at times but it paid off. Strick routines and set his limits based on how he felt on a given day.