Book for 11-year old

[CalmShambala]

My DS (11) has to choose a book as a leaving gift from school.
He is an advanced reader and quite mature and the school has been OK with him taking in books that have been out of his age range in the past.
I am struggling to think of a book as we have most of the ones that come to mind.

He has read all the Percy Jackson, Lord of the Rings, The Hobbit, Lord of the Flies and what I call classic books such as Treasure Island, Robinson Crusoe etc. He really loved Lord of the Flies and has a lot to say about it.

I have read some of the threads on here and I don't think the school is going to approve of buying him To Kill a Mocking Bird or anything else like that. I would however, like his gift from the school to have some meaning and be something he keeps and reads again and again. Something with meat on the bones rather than the latest David Walliams book.

Any ideas?

Ds likes books by John Flanagan and Rick Riordan

Here are some suggestion from what my son loved
Wonder by Palacio
Goodnight Mister Tom
Or I am Malala?
The Half Brother
The Martian

The Crysalids

DS's leaving year 6 book was The Accidental Scientist.
Curious incident of the dog...
Left field option Absolutely true diary of a part-time Indian. About the high school experience of a boy who lives on a reservation but goes to 'white' school. He is bullied but there is much humour.