I'm wondering if my PO can access my bank account information and debit card statements and purchases without my permission?

I suspect he has permission as a condition of your parole.

He can not do it without permission, but he has it, a PO can even come in and search your home anytime they want without a need of a search warrant ( parole officer)

The bank may of course require them to have to, to release it, but he merely goes in to the court and the judge will sign the order without even asking why for a parole officer.