When signing the waiver, does the parent have to be there? Or just an adult?

Just an adult is fine

Just a adult. Btw a wavier DOES NOT need to be done everytime u go. Stays active for 1yr.

A legal guardian. Be careful to get a release from each parent, if possible. We live in litigious society and if an accident happens, parents are likely to come after someone. I think you can download the release from their website.