So you can listen to your own opinion, or you can take the expertise of people who have been around this block a few times: one of those things will help with admissions and the other won’t.
“8 clubs and a sport” can = nothing if you don’t show commitment over time / growth / leadership. Some breadth is a good thing- but depth is also important. Focus your EC efforts on a couple that really mean something to you- and challenge yourself in them. If you want to challenge yourself in math, get into some competitions. If school is too slow & boring see if you can move up a level. Take a summer course that lets you move up a level.