I was on my parent's marketplace plan for 7 months of the year and am not dependent on their tax returns. I did not get my own 1095-A and so when filling out the household information, there are 5 months where I was not part of the policy but there are still values there since my parents are still on it (they are lower amounts accounting for the fact I am not on it still). Do I fill out the 1095-A as is or should I leave these are 0 since I didn't have that policy for those months?
You will need to fill out the 1095-A as it is on the form.
Then you will be able to allocate an amount to you and your parents. You parents will do the same. You can claim 100% or 0%, they can do the same as long as it adds up to 100%. Many times parents paid the premiums and will allocate the full amount to themselves, while the kids just enter the form and allocate 0%.
If they are not claiming 100%, then you can allocate the percentage based on the actual amount that was related to you and they would allocate the rest to them. For example, if total premiums were $10,000, and you were on the policy for 7 months, then their premiums dropped by $200 a month when you were removed, your amount would be $1,400 or 14% of the premiums. Therefore, you could allocate 14% to you and they could claim 86%.