For D1 basketball and baseball (especially at these schools) the coaches often recruit 8th graders! Most basketball D1 players at these top schools have played AAU basketball for years or attend special high schools devoted to basketball, are on a path to a specific D1 school for years. Senior year is much too late.
Are there schools where basketball players walk on? Sure, but these schools are not among them. And walking on doesn’t help with admissions