I try to get 8-9 hours a night. I usually go to bed at 10pm and wake at 7am. I wish I could sleep less, but I just feel terrible when I do. At least I hope that I'm more productive the time I'm actually awake.
Take a look at your diet. I cut out refined sugars and switched to a (mostly) LCHF diet and I can now function at nearly 100% on as little as 4 hours of sleep. Most nights I get 5-6 hours and can usually function at 100% as long as I get a good 7-8 hours once every week or so.