The plan was to send my oldest to public school. I didn't like the preschool programs, so we had until kindy. Then I realized it would be a terrible fit for him. He was a wiggly, impulsive, active boy. And though I knew he didn't have ADHD, that doesn't mean the school would know how to handle him. He has some sensory issues and they still weren't fully under control at that point. He was seeker with most things, though an avoider with some, so he would make his own excitement if there wasn't enough stimulation. This meant sitting still and paying attention did not work well! We unschooled for kindy, so it was just parenting and following his lead. Since he needed more activity, we made sure to do things like go to the park every single day. I even included rough-house time when I would wrestle with him to help with his touch need. By putting in activities to meet his high stimulus needs, his behavior drastically improved. His impulse control improved a lot as he got older. A wiggly first grade boy can actually be developmentally normal and not ADHD too - a professional will help you with that. However, the fast that he's "starting" to be labeled makes me wonder about it. Was he too wiggly in kindy too but they were willing to work with him? Either way, you would need management techniques for home. If he's been impulsive and active all along, then you likely have some parenting techniques that you've been using that you can apply to homeschooling. If you're struggling with him at home for other things as well, then a therapist can also give you some techniques in working with his ADHD.
For first grade, we did as much child-led as possible but not pure unschooling. We did use a formal math curriculum - that was the only subject with any worksheets. I would have him sit on an exercise ball to do a couple of problems and then chase him around the house for a couple of laps as his reward for doing the problems. Then repeat. The exercise really helped him focus better. As far as working from home, I had to work with my child for all of his work at that age. The same was true of my second child, but she didn't have the wiggly issue. It took 90 minutes total for my oldest and 60 minutes for my middle child to get in the core subjects. We didn't do it straight, but with breaks added in too, so it was spread out. Doing subjects he was interested in helped too. I'd ask him what he wanted to learn about and we would do that. If he had no idea, then we would head to the non-fiction kids section of the library and let him pick. We didn't do work sitting down, at a table, with the exception of math and the exercise ball. (Though he later switched to lying on the floor for math and then a chair at a table at 4th grade). We would read books and talk about things outside, lying on the floor, lying on a bed, or even while he was on a pogo stick if it was something he just needed to listen to.
We played around with times to pick the best attention times. I thought mornings would work best, as that's the case with most homeschoolers I know. It was a disaster. I tried evenings, as hubby was home and could watch the two younger kids then. But his brain did not have focus then either . We settled on having an early lunch at 11am and not starting until right after. That worked wonderfully. Now that he's older - he's in 5th grade - he is able to do some work in the morning as well. His workload is much bigger but so is his focus. I do keep his easiest subjects in the morning though, as his focus is still better in early afternoon.