In a seller financing deal, because the seller is financing the deal, there isn’t necessarily a credit check involved. This is the decision of the seller. However, if you’ve been renting the place for a while, there will probably be no need for a credit check because you and the seller already have a relationship, and the seller knows your payment history.
For the short term
Seller financing deals are often done when buyers have poor credit and can’t get a loan from a bank or mortgage lender. If that’s your story, you will probably need to raise your credit score eventually. Usually, seller financing deals are short-term.