I second the recommendation of iStudiez. My son just finished 8th grade and started using an iPad for school the second semester. iStudiez is the app he uses for his planner. There used to be an app called inClass that was PHENOMENAL, but I can no longer find it. It was a planner, but also kept all notes and everything needed right in one very organized app.
I’m sure Alan Brown shares more great apps in this webinar replay/podcast too:
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism