I'm no expert on this stuff...
Without reading a biography of the head Mullah, it's hard to know why he ordered the Buddahs destroyed. [link|http://www.google.com/search?q=cache:PdL8MPhRMd0:www.supportersofshariah.org/eng/asap/smashing.html+Afghanistan+buddah&hl=en|Here's] a story attempting to justify it (from Google's cache).
I don't think the Taliban is too interested in America's wrath, while bin Laden clearly is. I think they're most interested in controlling Afghanistan with an iron fist. They enjoy bin Laden's support, and protect him in turn. So I don't personally think that the Taliban was directly involved with the attacks on 9/11.
They certainly appear to have protected bin Laden for years, so in that respect they are responsible for bin Laden's actions.
Best of luck trying to figure this stuff out....
Cheers,
Scott.