George strikes me as sensitive and naturally shy, with a lot of George VI in him. Spencer school tradition is irrelevant to George’s education. The family might well depart from tradition to ensure his best possible path forward. And - pragmatics need to be addressed - that path is likely to include never being King.
I believe that William and Catherine will choose the best fit for each of their children even if that means that they choose a different school for each child.
I wish that Charles and Diana had opted to really choose the best fit for each of their children, so Harry wouldn't have struggled at Eton. Gordonstoun would have been a better fit IMO.