If you want all schools to be open until six, you need to take it up with each of the thousands of local school boards in the US, along with the many thousands of charter, private, and other independent schools.

The federal government has no policy-making authority w/r/t education in the United States. And if such authority did exist at the federal level, the appropriate place to start would be Congress, not the executive branch.

In reality, of course, you'd never be able to create a universal policy to reflect your particular vision of how education ought to work, and that's a good thing.

Bureaucratic authority, no. Influence to the point of defacto authority, yes.