You probably rapidly charged it. It tricks it to think the battery is full while it really isn't. Don't use a rapid charger. Plug into your PC using usb charge, and try again. IF not, let it drain to 0%, then let it recharge. Try to force it to reset the battery detection.
Considering that it's a 9000, the battery's probably old, especially if you use rapid charge, it tends to wear out the battery faster. If you treat it well, like I did with my 9550, the battery still holds for 3 weeks on idle.
I would say if draining and slow charging doesn't work, then get a new battery. A simple test is take the battery out, put in on the table and try to spin it. If it spins like a top, it's dead, and you need a new battery.