Ok, after getting IE9 preview 3 installed last night, I was able to update my SVG scorechart. I'm pleased to say that I would now unequivocally classify IE9 as a browser that supports SVG. Supporting gradients, patterns, masking, clipping and more actually gained them quite a few points.
I'm also pleased to see that they support conditional processing (the <switch> element) so you can see at a rough glance what feature strings they claim to support by accessing this page I made years ago. Not a bad feature set for first time out! Kudos to the IE team!
And they support <canvas> too!
In my brief look at IE9 while running through the SVG tests, I would say their biggest areas to improve on before final release are text (especially text selection) and DOM. Though Alexis assures me that they do pass quite a number of SVG torture tests.
Hey, now that we have all major browsers supporting basic SVG rendering, it's really time to ramp up the effort on SVG Torture Tests to ensure DOM coverage and corner cases. We are looking for someone to lead this activity in the SVG Interest Group.
Oh, and I would love to have SVG-edit working in IE9.