.. If you know where you are moving find the local HS team's facebook page and reach out to them (It could be run by somebody in the booster program or a coach... but they will get you all the information you need to hit the ground running). IMHO, HS football is one of the best ways to build lifelong friends.
HOWEVER, just remember most of the kids on the team will have been working out for YEARS together. So the better shape your kid is in, the better chance he has. His size and speed will determine where they stick him.
HS football is all about mental toughness and working through adversity. Too many parents think they can 'push' their kids through the hard stuff... but it comes down to the kid. It's also not about being 'THE GUY'... Over the years some of the kids I've admired most are the kids that never took a starting snap, but still made huge impacts on the team (and their teammates)
If you are moving to Utah there are dozens of agility and training programs around SLC/UT county for kids.