As part of my role as a teacher in a sixth-form college for gifted students, I have the option of requesting books be bought for the library. I do also talk about EA with interested students, but am primarily interested here in books that people feel might inspire students who haven't otherwise engaged with effective altruism. As well as obtaining recommended books for my own school's library, I am exploring the possibility of donating highly recommended books to the libraries of other very high performing sixth forms, several of which I already have connections with, and several others I could easily make.
The school already has copies of the 80,000 hours career guide, The Life You Can Save, and Superintelligence, though I am still interested in comments (positive or not) on these. The more details you can add about why you've recommended (or not) a book, the better.
Terry Pratchett, particularly The Amazing Maurice... DFW, Infinite Jest; J. S. Foer, On eating animals; Jonathan Franzen, Freedom; Cixin Liu, Remembrance of earth's past.
My point is that by "gifted teenager" you probably mean someone intelectually gifted, but not necessarily morally aligned; moreover, teenagers (everyone, actually, but teens more than anyone else) may rebel and resist if it's too obvious that you're trying to lead them to a specific mindset. So, if that might be the case, perhaps you should consider what kind of literature would nudge this teenager into EA-thinking first, and then what kind of books could shape their thought.