I think a great book (probably not for the holidays though, given the subject matter) would be the Diary of Anne Frank. I read it when I was that age. It was deeply moving.
The Hobbitt Series was a fun read.
The Hobbitt/LOR series is a great suggestion. It never crossed my mind. I read it as well around that age. I don’t know about the Diary of Anne Frank. I’ve never read it. Would you recommend that book for a child who occasionally has nightmares (2-3 times a year)?
The Once and Future King
T.S. White
Captains Courageous, Kim, The Light that Died
Rudyard Kipling (In fact, anything by Kipling)
The Honor Harrington series (Horatio Hornblower IN SPAAACE!!!!) Honor, duty, courage in a Royal Navy in the far future with good hard science mixed in. The Hero (heroine?) is female, and a great positive role model.
David Weber
The Hyperion series (Lots of philosophical insights but may be too advanced.)
Dan Simmons