Wow, this far into a thread on this topic and no snarky references to "lil' Gretzkies"!
I assume we are discussing playing up from Squirt A to PWA or AA (I wouldn't recommend skipping Squirt A altogether or playing up to PW BB),
IMHO, ever since checking was removed from PW, the difference between Squirt A and PWA are in degree rather than kind. (PWAA is another matter, and what you choose to do there is a different calculus based in part on whether there is anything resembling flighting and whether the player is on a birth year team). Because the kids are a bit bigger, the game is somewhat faster, somewhat more physical and in general there is a little bit more team play. There is also less pure skill. It makes for a logical next step forward for most players who have had success at Squirt A, regardless of whether they were 9 or 10. Looking back at my son's play up year, most of the kids who played up into A are now AAA players, and many are among the scoring leaders. There are also a couple of kids enjoying success at AAA who did not play up, so its not as if there is only one right path.
To me, the critical threshhold question is whether your player has already had a successful Squirt A season. I couldn't disagree more with the "will he dominate AA" standard. I have seen firsthand too many kids who had a successful but not dominating season at Squirt A play up to PWA, and go on each year to progressively more success.
To me eye, success would mean being one of the better players on the Squirt A team, and without social issues in the Squirt A locker room. Is he getting good TOI? Special teams? Critical situations? Leadership role?
If your player passes that threshhold, then there is the question of where he projects on the PWA team. If its not similar to the role he had on Squirt A -- better player, good TOI, special teams, etc) then I would not put him on that team. Its the same inquiry I would make of any new coach/team regardless of level.
Are there any yellow lights - is your player on the smaller or younger side? Is he not as coachable? Does he have issues maintaining focus at practice? Is hockey not a major passion for him?
If your player was already successful at Squirt A, remember that you are re-starting the Squirt A experience. Is repeating the same types of practices with younger kids beneficial? Or scoring goals with habits and moves against younger kids that won't work at PW? Are you trying to play up to keep up with another group or to make up for a lack of development at Squirt A.
Good luck to you and your player!