We've been down this road so many times...

Yes it is deplorable that reclassed kids must use a younger venue to be able to become visible for recruiting purposes.

It's not going away anytime soon.

The only immediate solution is for dads of younger than 2017/2018 to get as much additional training as possible. Showing up for practice is not going to be enough.

Do what we did: invest in the best private coaching you can for your sons position.
Invest in an early age appropriate private conditioning program with a personal trainer.

Get him on the best team he can qualify for where he has a realistic chance of starting or at least get even playing time (those clubs are out there)

Maintain strict academic standards. No high grades = no lax or other sports. It's a priveledge, not a right to play.

Look for any signs of stress. It's supposed to be fun. If it's not; find out why and try to work towards a solution.

Let him find his way; don't push.

Be 100% supportive; win or lose.

If he's good; he will kick the butts on the older kids who have to play down. Typically, their skill sets don't match their physical maturity advantage (why would they be playing down instead of with their peers?) and are easy prey for good players.

Be positive.