Re: OP, as a Stanford alum and interviewer, I can tell you that neither sports nor entrepreneurship is a requirement for admissions. I had zero entrepreneurship and only a couple semesters of non-varsity sports; many of my classmates had neither. For the vast majority of American schools, there are quite few few “must do” things to get in, aside from the obvious ones posted on their admissions websites (e.g., take the SAT or ACT). Many schools including Stanford focus on diversity–you obviously won’t get a very diverse class if everyone accepted was a varsity athlete who started a small business.
If you’re interested in admissions, you can take a peek at this article which was published in our alumni magazine towards the end of my undergrad time there. I’ll let you interpret it as you will. Good luck with your application cycle, and remember that most people love their college experience regardless of where they go. That said, Stanford is an excellent place to go. 
https://alumni.stanford.edu/get/page/magazine/article/?article_id=66225