I think his swing is more than solid for a 11-12 year old. It's a higher pitch, he naturally comes out of his shoes a bit to stay on the path of the ball. Nice indicator of hand-eye & athleticism. A lot of good going on here. As he gets stronger, in particular his core and legs, he'll be able to create greater torque, allowing him to drive and extend through the ball.
Keep the athleticism going, play, play. Caution: too much instruction by too many different instructors talking to your son at this stage will make your son too mechanical. You'll take away the good athletic things going on in his swing! Take the time and find a good hitting instructor to work with your son over the off season. Working one or two pieces at a time allowing him to maintain his athletic ability and love of the game.
We went through a similar thing, we took our time and found a good hitting instructor that could communicate with my son, he was also accessible.
Nothing to be concerned about here...enjoy the journey.