If your principal residence is held in trust
If your principal residence is owned by a grantor trust, and either you or your spouse is a trustee, then you would qualify as a homeowner.
If your principal residence is owned by a grantor trust, and you or your spouse are not Trustees, then renter rules are applied when determining the allowable credit. For example, you're a former owner who creates a life estate and puts property into the trust for your children's benefit.
Generally, if you're under the terms of the trust, you pay to the trust in lieu of rent, you may treat these payments the same as if they were rent and should follow the renter rules when filing for the credit.
Renter rules also apply if the principal residence is owned by irrevocable trust, regardless of whether you or your spouse is a trustee.