The expenses would probably be qualified. See Qualified Education Expenses on page 51 of Publication 970, which is in Chapter 8, which covers QTP's, which is the IRS term for 529 plans:
https://www.irs.gov/pub/irs-pdf/p970.pdf"Generally, these are expenses required for the enrollment or attendance of the designated beneficiary at an eligible educational institution. For purposes of QTPs, the expenses can be either qualified higher education expenses or qualified elementary and secondary education expenses."
"Eligible elementary or secondary school. An eligible elementary or secondary school is any public, private, or religious school that provides elementary or secondary education (kindergarten through grade 12), as determined under state law."