I providing following steps which would help you to remove Internet Explorer 9 beta from the computer of yours. You have to launch the command prompt on the computer of yours. You have to click on the Start button and go for Run and enter CMD and hit enter from the keyboard. Now copy paste the following command on the command prompt and press enter.
Make sure that you are executing the command with as Admin of the computer.
FORFILES /P %WINDIR%\servicing\Packages /M Microsoft-Windows-InternetExplorer-*9.*.mum /c "cmd /c echo Uninstalling package @fname && start /w pkgmgr /up:@fname /norestart"