There are no right or wrong answers. Even if your DS had scored in the range you expected, it would not guarantee that the school using the scores as a minimum requirement would have been the best fit.
So much of it depends on your child and on the school itself. Since the WPPSI can not be retaken for at least a year if not two, those are the scores you have - which is just a snapshot of your child at that one point of time.
Without knowing anything about your DS other than the scores - which is only a partial picture - all I can suggest is not to slam the door on TAG schools/programs if you think he belongs there, but not to focus DS's educational setting solely based on whether he would go into TAG program or not - regardless of LOG, but rather - if the school would provide what your DS needs.
I have read enough comments people post on various TAGs to know that it does not work for all kids, regardless of LOG. And each child is unique and some schools that don't have formal TAGs can sometimes work better for children who are advanced than schools that have TAG programs simply because they ended up in a school with personnel that supported their children's needs *appropriately*.
Also - if the school you place him into for next year does not work out, you can still change schools (at least for most people, this is an option).
