This post gives you links to Group Policy Settings Reference Windows Internet Explorer 9, Toolkit to Disable Automatic Delivery of Internet Explorer 9 and Internet Explorer 9 FAQ for IT Professionals.
ie9
Microsoft has re-imagined the role of the browser with Windows and Internet Explorer 9 to deliver an experience that makes the Web feel as native as consumers’ favorite PC applications. Using full capabilities of Windows and hardware, IE9 enables a version of the Web that is faster, cleaner and more trusted..!
This discussion was primarily around the Performance improvements, HTML5 significance, Integrated SVG, WOFF (Open Font Format) and the Hardware Acceleration features.
Includes expanded support for HTML5, hardware-accelerated graphics and text, and a new JavaScript engine. IE9 introduces GPU-powered Canvas & GPU-powered