Why do I have to sleep 9+ hours to be rested?

Most people manage quite well on 7 or 8 hours of sleep per night but some people actually need 9 or 10 hours.

Everyone's natural rhythm is different, and you might actually require 9 hours.

However, take a look at what you're eating. Does your diet contain a lot of fruits, vegetables, and natural fiber? These are things that keep your system moving. Lots of starches slow you down.

Exercise may help you to require less sleep as well. You'll sleep more deeply and feel more refreshed when you wake. It can be as simple as a 30-minute walk after dinner.

It depends on your age. Sounds like you're a teenager. You're sleepy because going through puberty causes your body to need more sleep so your body can function more properly as it's going through puberty

I need 10 and I'm an adult.

Einstein needed 14.

Edison only needed 4 (he stole most of his ideas).

Take a nap during the afternoon if you can or go to bed earlier.

That's just how your body works...suck it up