Do you mean the battery is discharging within 8-9 hours? It's possible that if you are using the phone heavily, it could burn down in 8 hours or less. Especially if you are streaming video or playing games or doing other things that are battery intensive. If it is sitting idle and burning through the battery that quickly try restarting the phone to make sure that some process hasn't stuck and is in the background using CPU cycles and burning up the battery. And of course, as with all cell phones, if the phone is in an area that gets poor cellular coverage, the battery will be consumed more quickly.