I realise it\'s an early release and unstable. I wouldn\'t dream of swapping out the default webbrowser control for IE9 in any other project, but in this case I specifically
The only way IE9 could install side-by-side is when it uses new GUIDs for the interfaces and coclasses. Which means that you cannot use WebBrowser, it has the GUIDs hard-coded.
There's one other option, using the AxHost wrapper. Right-click the toolbox, Choose Items, select the COM Components tab and locate IE9 in the list. No idea what it might be called, the old name was "Microsoft Web Browser", serviced by c:\windows\system32\ieframe.dll
You'll have to make do without the friendly WebBrowser and HtmlDocument wrapper classes.