The answer is, no… Not exactly.
According to Wired, W3C had only prepared a limited test for HTML 5 specification. The seven tested elements were attributes, audio, video, Canvas, getElementsByClassName, foreigncontent and XHTML5. There are more HTML5 elements out there but they were not tested and these specs are not even finalized yet so it only gives us a glimpse of what future browsers can do.
IE9 is a very promising because it embraces web standards. It’s a big improvement compared to its predecessor. Do you agree?
Read more information about HTML5 and CSS 3 support in Internet Explorer 9 here.