I won't comment on 9 year old teams, but I would recommend that any talented player should try to find the best possible competition at age 13-14 these days. This is something that has changed over the past several years.
Everyone talks about the best or elite level teams. It's really not up to you which team is a possibility. That is all up to the talent level of your son. Sure there are teams where you can buy a roster spot. These are not among the better teams.
I understand why people call our tournaments showcase tournaments. The big ones are the most heavily scouted events in baseball. I understand that teams go and want to get their players seen. But do not kid yourself, the best teams are in fact there to win! For those that make it to the playoffs it becomes very obvious how important winning is.
So these big tournaments really are just baseball tournaments. They just happen to have more scouts and college coaches in attendance. And even those not in attendance can easily follow or find out who the top prospects are.
To me, the first question shouldn't be how important it is to play high level. The first question should be is my son talented enough to play at a high level? And yes, it is my opinion that a talented player should seek the best possible competition and the best possible exposure. In fact, a little research will show that is the path most top prospects take.