Every holdback has an advantage, you have to either get over it and move on or do the same with your son. I would chop my hand off before forcing my son to repeat a school year to give him an advantage on the lacrosse field. Deplorable IMO but many willing to do it.
I may be naive but I don't think many people reclass their 2023 kids for lacrosse purposes. I think it typically happens in kindergarten and is for maturity reasons. My understanding is the reclassifying happens in 8th / 9th grade years.
I am surprised someone from PT would shift to LI Express. PT looks like a pretty legit program to me.