Advice for College Admissions

Hi,
I just wanted to go on this site and get some possible feedback to help me in the coming years; next year I’ll be going to 9th Grade at my dream school Hotchkiss. I plan to major in physics, but I wanted to see if anyone had any advice that could help me build my resume for my senior year. I already plan to join clubs like the Science Olympiad, the Math Team, a Political Union, and Speech and Debate. I want to apply to very competitive schools (Yale, Harvard, Stanford) and I was wondering what advice you would have for me. Are there any classes I need to take? Any clubs I should start that would really help? How much should I study for the SAT? These questions are all of course basic and just to provoke some thoughts, and I might be asking this too early, but any input would help me so much. Thanks!