the 529 plan outcome has nothing to do with whether she is a dependent or not. That will go on the return of whomever's social security number is on the form
with respect to AOTC (which comes down to the 1098T) form, as noted by @DaveF1006 , you certainly have the right not to claim your child as a dependent, but you give up the AOTC benefit if you do that.
if the student is a dependent, then you claim the benefit. If you chose not to claim the student, then no one can claim the benefit. If the student can't be claimed by anyone, only under that circumstance are they eligible for the benefit.
Do be careful of the 'double dipping' when calculating the AOTC credit and the 529 distribution - it can be tricky - plenty of posts here do explain it.
