Hi suevv,
You've already received great advice above - I've got just one thing to add. We weren't in exactly the same place but a similar sorta place at around the same age with our ds. We were advised to change his school (due to gifted + 2e issues), but ds did not want to switch because he *thought* he was happy where he was. We made a few changes at his school but didn't take the advice to switch schools. As the years went by, the issues that we'd worried about that led to the recommendation to switch grew, and toward the end of 5th grade, ds came home and told us (parents) that he wasn't going back for 6th grade, and shared a litany of complaints about being bored with the level of intellectual discussion and being frustrated with teachers not caring about helping etc.
So we made the move to switch schools at that point in time, and landed at the school that we'd considered way back in 2nd grade. It worked out *so* well, and I can't tell you how many times I've kicked myself for *not* making the switch when it was first recommended. Even ds told us, on his own, that he'd wished he'd been enrolled at the school years earlier (and ds never knew it was the school we'd thought about switching him to).
JMO, but if this other school is an exceptional school or something you really think would work well once he's there, I'd go ahead and consider making the switch. I *wouldn't* have taken him on the school try-out day Monday, but I would talk to the school as you have, let them know what's up, and see if they'll work with you in giving your ds some time.
The other thing I'll throw out there - not that it's meaningful at all for your ds, but fwiw, each of my three kids had a best friend in early elementary that I thought would be their bff's literally forever. The only friend from early elementary that has stayed a constant in our family's life is a friend who is the daughter of one of *my* friends, so our kids see each other more for the parents' sake than for any type of connection from school. So I wouldn't necessarily pick a school based on friends unless I had concerns about my child's ability to make new friends in general. However.... fwiw.... we had those types of concerns with my ds, ad his best friend from early elementary (who was a big reason he wanted to not switch schools) just naturally drifted into other friendships by 3rd grade and was totally out of my ds' life by 4th grade other than peripherally. My ds continued to struggle with friendships - at that school. When he moved on to the other school, he fit in easily and made new friends. None of which might apply to your situation or your school choice, but just something to consider.
Best wishes,
polarbear