Tell me how to install and uninstall the driver software.

See "Installing the software" in this unit's operating instructions for the installation procedure.
The operation instructions can be obtained from the following Pioneer DJ page.
DJM-S9　Manual

The procedure for uninstalling the driver software is described below.
Uninstall:
Windows 8.1/8/7
1. Open [Programs and Features] in the Control Panel.
2. Select [Pioneer DJM-S9 Driver], then click [Uninstall or change].
3. Operate following the instructions that appear on the screen. If you are asked for the administrator’s password or a verification, input the password or provide the verification information.

Mac OS X 10.10/10.9/10.8
1. Double-click the uninstaller ([DJM-S9 uninstaller.app]) to launch it.
*The uninstaller ([DJM-S9 uninstaller.app]) is stored in the disc image ([DJM-S9_M_*.*.*dmg]) downloaded when the driver software was installed.
2. Operate following the instructions that appear on the screen.
3. After uninstallation is completed, be sure to restart the computer.