Depends on the kid, and depends on what you mean by suitable? Lucy will be written with a young adult-ish sensibility. There will be some violence but it will by no means be splatterpunk. There might or might not be kissing but definitely not explicit sex. It's likely there will be some mild swearing, and some colorful language that does not actually use modern swear words. I'm afraid I can't yet predict how the story will rate in terms of how scary it'll be, how dark the themes, etc.
I'll let my own kids read it, but then again I also let them watch us eg. play Assassin's Creed? Your parenting may vary.