I wonder if I can train my body to live on 5-7 hours of sleep. This is from sleeping 9+ daily.
you can! it just sucks, I used to sleep 8~9+ daily, but then i started taking melatonin for sleep aid (cause i also had trouble falling asleep as well), and It's gone down to about 6~8hrs regularly. Which is about normal levels, (so I'm sleeping 1-3hours less, but actually waking up feeling fully rested) Another thing that really helps is following a schedule, Be strict on yourself, If you tell yourself you are going to get up at a certain time, don't keep hit snooze button for 2hours, just get up and do it. It'll save you a snowball of problems later (like not being able to sleep the following night because you slept in)
Another thing to note; I started going back to the gym pretty regularly and I believe it's helped a TON, mostly with the issue of falling asleep at night, As I now feel like going to bed at night after pushing myself in the gym during the day.
Honestly I'm in the middle of this battle, and it sucks lol. But between taking melatonin and going back to the gym regularly Most of my sleeping issues have gone down pretty dramatically, Prior to taking melatonin i wanted to die, I was literally sleeping 3-4days a week (and when i did sleep it was for 10hours+) everything was just random, no control over anything, randomly tired, randomly active. It sucked lol. (this was when i was actively trying to fix my sleeping without any kind of change to my day2day lol)
tldr; In order to change your sleep, something else has to change in your day/body. Something something equivalent exchange.