Well, I've never dealt w/ a 9 yr. old on that flight, but I'm thinking that music or video games, or a good book if he/she is a reader, would be the best choices. Also magazines about hobbies or special interests are good for occupying the older school-age child. As long as your plane actually belongs to
Virgin Atlantic, there should be plenty of TV and Nintendo games on the seatback. They can't play them for the first and last 30 minutes or so, but otherwise you should be fine.
My 6 yo tends to like many of those same things, except that he's too young to space out on music alone. The video games will keep him happy for an entire flight, though, they are always a winner. He also likes book/cassette or book/CD combinations with a set of headphones, that is kinder on the people around you than you reading aloud yourself. (If you have a recorder, you can make your own cassettes for books you know your child would like.)
DS likes maze puzzles a lot; I've gotten him maze books and downloaded maze sheets off the web for him, too. That age is getting a bit old for crayons, but I find that boys, especially, like the how-to-draw workbooks that simplify the drawings step-by-step. You can get them at the library and photocopy many of the pages if you want to keep your luggage weight down. Several sharp pencils and a good gum-rubber eraser are a must for drawing practice, and also blank sheets of paper, of course; onionskin being lightest in weight. Hand-sized toys are good, but nothing w/ tiny pieces that cannot be lost; as they are guaranteed to get lost on an aircraft.
Lastly, all the food you can carry. (Just FYI, you won't be allowed to bring fresh fruit or dairy off the plane when you arrive, you'll have to finish it or leave it on the aircraft.) Snacks are always important for children, and the airlines never seem to provide food at the times they want it.
It should be easier going home, as they should sleep on that flight. You are in a better position as the daylight flight is on the outbound journey when they are still excited and on good behaviour lest they get some of the holiday treats withdrawn. In our case, the flight home is daylight, and they are bored and tired of travelling by that point.
