In my opinion, it really doesn't matter where the "most" scouts are. If that's what you're asking, the clear answer is Jupiter.
If I've learned one thing, it only matters where the coaches are that the players have had previous contact with.
That said, odds are, "your" sons coach will be at Jupiter. He'll only come watch your son if you have steady communication with him re: your son's interest in playing for him, and the team's schedule while in Jupiter.
Unless your kid is a superstud don't count on being discovered anywhere. Just work on cultivating the relationship.