07s are allowed to play up to Pee Wee. With AA tryouts in ten days, it may be a little late to get him the exposure that he needs, but get him to pre tryout clinics for A and AA teams immediately.
6607 is 100% correct, "get him to pre tryout clinics... immediately." However, to play devil's advocate... was his birth year the ONLY reason the 3x3 opportunity was declined? A few questions I would ask to determine my encouragement for or against the play up if I may.
1. What is your player's height and weight?
-- since you brought it up, maybe the 3x3 director was concerned about the size of your player so he used the 2007 excuse knowing it contradicts CAHA/SCAHA's Guidelines. Birth year is NEVER a good reason a player should or should not play up, but people often don't know how to say, NO.
2. Did your CLUB have a SquritA team? and was your player a dominant and/or impactful player on his team??
-- I understand there were 8 SquirtA teams last season with one moving back to BB who ended up dominating that division. 4 of the Top 8 BB teams did not have a SquirtA team, thus you may have some reason to question your play up.
3. What does YOUR Club director suggest you do? What does your head coach from last season suggest you do??
-- you mentioned "He is excelling... (skill wise) which raises the question, he may be in off season clinics/camps/lessons. What does his current clinic/camps/lessons Coach suggest?
I just can't judge by what has been posted whether he should play up or not. If I had to choose, 3x3 director was not ready with a good reason and so blaming his birth year knowing your player would be a Squrit MAJOR this upcoming season. Nonetheless, if he can play with the big boys, by all means... play him where he is challenged and can have fun. Good luck with your decision.