If Internet Explorer 9 is crashing or not opening, a quick reset will return Internet Explorer 9's settings to their default level and possibly resolve the problem for you:
How to reset Internet Explorer settings

If some pages aren't displaying all of the content of the page or if some pages aren't displaying correctly, the guide below can help to resolve these issues:
Why do some webpages look incorrect in Internet Explorer 9?

In some circumstances you may need to uninstall Internet Explorer 9 to get back to a previous version, however, when they try to uninstall IE9 through add/remove programs, IE9 is not in the installed programs list. Internet Explorer 9 is listed under Installed Updates. To uninstall IE9 use the following steps.

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.

For additional information on installing and uninstalling Internet Explorer 9, visit the following link:
http://windows.microsoft.com/en-US/internet-explorer/help/ie-9/how-do-i-install-or-uninstall-internet-explorer-9