As Kevin pointed out, look at the iPad/ computer USB connection.
Error 9 pops up when a communication between your computer's USB port and the iPad is lost. This usually happens when the USB cable is pulled out when there is, say, syncing with iTunes. It can also happen when the USB cable is damaged, or if the USB port is faulty.
What you need to do is to go through a process of elimination:
** Obviously check by reconnecting the cable.
** Check that the cable is not damaged. Connect the cable to another USB port on your computer. If still no good, to make sure, connect to another computer. Of course, check the USB port for any dust/obstruction.
If there is no solution this way, you may have to accept a sadder reality - that your iPad is the problem and may need to go in for exchange. Hope not!
Regards, Andrew
If you have other iOS devices, try the cables from them on your iPad to eliminate your cable as the source of the problem. Without checking with another cable, there's no way to eliminate the cable as the source of the problem.