IE9 is currently a pre-release software and you may need to remove it to get back to a production environment. However, when they try to uninstall through add/remove programs, IE9 is not in the program list but listed under Installed Updates.
Steps to Follow
1. Close all programs.
2. Click Start, and then click Control Panel.
3. Click Uninstall a Program under the Programs category
4. In the Tasks pane, click View installed updates.
5. In the list of installed updates, double-click Windows Internet Explorer 9.
6. In the Uninstall an update dialog box, click Yes.
Note If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
7. Follow the instructions to uninstall Internet Explorer 9.
8. When the uninstall program is finished, restart your computer.
9. After you restart your computer, open Internet Explorer.
10. Click About Internet Explorer on the Help menu. If Internet Explorer 7 or 8 appears in the About Internet Explorer dialog box, then you have successfully completed the uninstall.