I'm on oxygen and just flashed matrix 9.0 bfs yesterday, battery life was terrible. Hopefully today after clearing battery stats we'll see an improvement
First charge cycle is always okay at best... Also you may want to try the cfs version instead of the bfs. bfs is the betas, experimental versions so they aren't always the most dependable.
FYI, I'm running Oxygen 2.3/Matr1x 9.0 cfs and here is my screenshot near the end of my first charge cycle.
Note: This was with about 1 hour of calls, a boat load of GTalk, played around overclocking to 1.46 Mhz and running some benchmarks (scored a 4700 highest) for about 10 minutes and downloading things from my Dropbox and flashing numerous zips and some web surfing. So not what I would call a very light usage day.