Also, it appears that when that page was first published IE9 did not pass 100% of the test cases, I really do believe that that page is an honest effort from the IE test team to highlight parts of the standards that are ambiguous or tricky to get right. I don't think it is the FUD that it at first appears to be.

For the record my main browsers are Chrome and mobile Safari, I only use IE when I need to test that something works properly in it.