Taliban did not do 9/11, and who did it, it remains unproven. Mullah Omar asked Americans for proof against OBL's alleged involvement and Americans refused to provide for either they never had any such proof or were too arrogant to do that. Mullah Omar sacrificed his government but kept his promise, promise of a true gentleman. America invaded Afghanistan and since then his men are fighting invaders just like Vietnamese fought, or Iraqi insurgents did.
And as far as Americans declaring everybody, who does not happen to toe their line, as terrorist is concerned, George Washington, the father of USA, was declared as terrorist by the British (against whom Washington was fighting) so lets not go into this joke of declaring terrorist for it means nothing.