Thanks for sharing the video, Dad, I really enjoyed watching that one. There are a handful of mechanics fixes that come to light right away - any decent instructor will easily get him on the right path. But any player who chews gum with that much aggressive enthusiasm is sure to be a great hitter some day.
Seriously, his aggressive approach with the big leg kick might not be ideal mechanics but it says a lot in a good way about wanting to hit the ball hard and that is so important at this age. If he really likes the game, some time in the next year or two, he'll want to get some good instruction to channel that approach in a more effective manner.