Not sure if you're concerned at all about content, but he may also enjoy Daemon and the sequel Freedom. They are both "what if computers took over the world" sort of fiction, but there are some graphic deaths. I read it right around the same time as Ready Player One and found them similar but from different perspectives. Kill Decision, by the same author, would also fall into the science in a cool (and scary) way!
Is he into Minecraft? My son enjoyed Minecraft: The Unlikely Tale of Markus Pierson.
For science in a cool way,
