Fidgets are an important part of managing or physical restlessness. But, they have to be “respectful” fidgets. Check out Fidget to Focus. It will give you many great ideas. But the short version is that your kids (of your) fidget needs to be something that isn’t visually or auditorily distracting to everyone else. I would love to click a pen all day, but that would drive the rest of the world nuts. Something simple like a squeeze ball or a piece of putty are great. Even a paperclip or a piece of string can work. I would suggest having a variety of things in the school bag to rotate through so your fidgety-ness doesn’t bet bored.
For artistic kids, doodling can be a great option. I think I’ve mentioned this in a post before, but that won’t stop me. I have a client who’s in middle school who is quite the artist. We used to meet in person and I always let her doodle while we were meeting. She would be staring down at her paper, not making eye contact. But I could tell she was paying attention. And, I don’t think I ever asked her a question and she wasn’t present with the conversation. Many teachers, parents, and neurotypical people find this rather disconcerting. I would suggest they got over it. If an artistic kid focuses better while drawing, let ’em do it.
Lastly, when doing homework on one’s own fidgets can be a little less respectful and on a larger scale. I had an instructor at my coaching school who told us that he never finished a book in his adult life until he realized how kinesthetic his learning style was. He realized that he could read if he was actively rocking in a rocking chair. Now he blows through books and enjoys them.