@Emimoo84 your son sounds like a well rounded intellectual boy.
I detest using the term fail or pass, because the children haven't failed anything, they've done exceptionally well. At that age, to go and sit an exam, is in itself a huge achievement.
Your son sounds like a naturally bright child, who will do well in any setting as long as his learning is facilitated.
Also, a lot of the uk doesn't have grammar schools, im originally from a city where we didn't know what a state grammar was (always assumed it meant private as it was just those schools with the grammar name!)
All those children from non grammar areas do well, including the ones that head off to oxbridge.
There are also those, who decide to reject grammar places because they don't suit or cater for the child. The drive to get children into grammar schools can be insane, and people somehow feel that once their child is at the school it is an automatic stamp to success (and we all know that's not true).
I also think, it's better to know at this stage about getting a place rather than wait until March. In our area, achieving the required standard does not guarantee a place, so your child can spend the next few months excited about the grammar and come March have their bubble burst!
Hope you find a school that suits your son, maybe he needs one with better art or sports facilities, and a lot of academies now offer much more in the way of variety.
Hope everyone else is doing well..