Our dep became nondep in June 2022. He is on our 1095A. Entering 100%,0% or 85/15 or leaving SLCSP blank all leads to blank 8962/no tax/paying back APTC. Need help!

Not sure what you mean by he became a non-dependent in June.   There are no "part-year" dependents.  He is either your dependent for 2022 or not your dependent at all.

We thought he would be a dependent and had him on our marketplace insurance but he graduated and got a job. I’m concerned that with his income he may now (or actually us) have to pay the APTC back.

Here are instructions on how to allocate the information on the 1095-A so your son can use that information to file the 1095-A form on his return. 

• Since you did NOT tell the Healthcare Marketplace (usually when they applied for health insurance) that your son was not going to be your dependent (because you did not know), he won't receive a 1095-A of his own.  
  • He will need to get a copy of your 1095-A and enter it on his tax return.  On the screen after entering the 1095-A, you will check the box indicating that the policy was shared by somebody that is not on his tax return.  It will then prompt him with further questions to determine how much of it is "allocated" to him (even if it is 0%). You as his parents would follow this same procedure.
  • If there was Advance credit received (column C of the 1095-A), your parents have the option to claim 100% of the 1095-A on their tax return, or to "allocate" part (or all) of it to your son.  If you both agree, the allocation can be anywhere from 0% to 100%.  If you can not agree and Advance credit was received (column C on the 1095-A), then it is divided by the number of people on the insurance policy.  For example, if the insurance policy covers 4 people, each person is allocated 25%.

@Taxissues2021

When I enter 0/0/0 his 8962 says Tax family 0 and the only other numbers are 0/0/0 in Part 4. The form just seems incomplete. If I enter 15/15/15 then he owes $800 and has to Pay APTC back.  If I enter 15/blank/15 then he owes nothing. I don’t know if because he is under our insurance as a family and our income, he wouldn’t have to pay more now that he makes money. If he were a dependent with tax return required to be filed his income would be added, my premium figure on line 7 would increase and I’d owe money if I took all the APTC. My feeling is that the I would owe money.  I just don’t know if it could come down to that family policies are cheaper and I (he) wouldn’t owe extra

Try different amounts for the percentage until you are satisfied with the results on both returns.  As @PattiF pointed out, you have the right to decide as long as you both agree.

• If there was Advance credit received (column C of the 1095-A), your parents have the option to claim 100% of the 1095-A on their tax return, or to "allocate" part (or all) of it to your son.  If you both agree, the allocation can be anywhere from 0% to 100%.

@Taxissues2021