Or it could just be natural variation in chronotype.

I had the same kind of sleep cycle when I was a teenager / young adult. I didn't have hypothyrodism or Grave's disease.

It gradually got a bit better as I aged and I'm down to needing a more normal 7.5 hrs of sleep.

Its still 9:20am in the morning, though, and I still feel like I got kicked in the face getting out of bed, which is entirely normal for me.

Just a small note, hypo is the opposite of hyper. Hyperthyroidism => more active & nervous, hypothyroidism => less energy, more weight gain, cooler metabolism so you want to stay under blankets all day.

I had mild untreated hypothyroidism for a year and it didn't help me get to sleep earlier.

... and don't let them tell you you MUST get your thyroid extirpated or radiated. In his case, the meds worked. In Europe and Japan, most doctors recommend meds. In America, most doctors recommend radiation or extirpation (surgery).

I have a sleep schedule like OP, but my thyroid is functioning perfectly fine...