It’s important to know that even good students can have ADHD. Boys and girls who behave well in the classroom can still struggle. Some of the things you’ve noted could definitely be tied to ADHD. They could also be explained by anxiety or even non-clinical issues. At this point, I’d ask yourself if this is something that is impairing him enough that you’re concerned about addressing it. If so, starting with a child therapist can be a great beginning. They can do a further assessment and figure out what to do next. If you need assistance finding one, there are some good posts here about finding a therapist.
It’s great that you’re so attentive to him and so eager to help. Way to be awesome!