@Mariah Even totally healthy people. Sleep needs vary.
My sleep needs began to increase a ton when my thyroid went haywire in my very late 30’s. My guess is your thyroid is tested more than the average person, so I doubt you would not know if you were hypothyroid. Although, look at your tests, if your TSH is more than 3.5 it might be in normal range, but close to being abnormal, making you a little more tired. Not that I’m saying necessarily treat it, but maybe consume a little more iodine if that’s the case? Look into it.
I’m also more tired when my red blood cell counts are low. Iron really helps.
I do think being sick probably affects your need for sleep. Your body needs to work on repairing your system. Older adults need less sleep because they are on the downward trend towards death. Lol. Their cells aren’t multiplying and dividing like young people for growth.
The sleep cycle is typically 1.5 hours. So, when you take a nap allow yourself 1.5–3 hours, and go through all the stages of sleep.
My nonprofessional opinion is needing 9 hours is not abnormal, but if you still feel tired with the 9 hours maybe there are little things that can help that, like checking for vitamin or mineral deficiencies.
Lastly, if you live in a cold overcast place, you might be affected by that, having more sleep needs in the winter. Or, if you completely protect yourself from the sun even when it’s sunny it might affect you a little too. I’m sure your doctor must check for D deficiency considering your situation, but if have never been told your D deficient, then maybe not. My assumption is you have been told that. I can’t inagine you’re not without supplements.