I agree with TJ's mum. Read your LO's cues... if he's a 45min. wonder and if you see him exhausted around 6:30, just put him in bed earlier.
My LO wakes up early sometimes, maybe an hour earlier than her wake-up time. This is the most awkward timing, hard for me to put her back to sleep after feeding (having slept for 101/2 hrs already). If she's ready, I'll then start the day.
Just keep a rough record of when your LO wakes up in the night. Sometimes, you can find a pattern... either wake-up hungry or habitual wake-up. I know my LO often wakes up around 4, hungry. Then I usually do a 2 DF around 3 to help my LO stretch her sleep.