It's possible that he's so incredibly smart that he finds many things boring, and that's not ADHD. ADHD tends to lead to a lot of disorganization (across different settings: home, work, school), plus attempts at compensation (self-medication, self-stimulation, etc.)
But just to be clear: This is a random list, it's not meant to be diagnostic. If these resonate with the OP or someone similar then it might be worth learning more about ADHD and talking with a professional. Please don't assume you have ADHD just because these things hold true.