My guess is IE 9 doesn't supports the 'lighter' globalCompositeOperation on the canvas which is key to making the effect work. Without it I bet the lines look pretty dull.
As it turns out, it works pretty well with the latest IE9 Platform Preview, long as you switch IE's user-agent to one of the supported browsers. I think you're onto something though, because it does look less shiny in IE than in Chrome.
