When my son was 9, he really enjoyed these authors and books:
The Lord of the Rings
Mark Twain
Robert Heinlein's "juveniles" (Starship Troopers, Tunnel in the Sky. etc.) *note that many of Heinlein's books are definitely for older audiences - the "juveniles" are a safe bet, though, and were written with boys between 9 and 15 in mind.
James Herriot
Isaac Asimov
Arthur C. Clarke
Animal Farm (1984 has some adult themes that you might not want at this age.)
H.G. Wells
King Solomon's Mines
My Side of the Mountain
Terry Pratchett
the Sherlock Holmes stories
Ursula LeGuin's "Earthsea" novels - some of her other work is absolutely aimed at adult audiences only.
Robert Louis Stevenson
His favorite magazines at that age were Smithsonian, Discover, National Geographic, Newsweek, U.S. News and World Report, and The Economist.
Yes, he's an interesting mix of outrageous flights of fancy and incredible pragmatism, lol.
