I don't think that there was any lack of information sharing at all. Many governments warned the USA of the impending attack - INCLUDING THE TALIBAN government themselves! Most people are not aware of that. It appears that the attack was ALLOWED to occur. The Patriot Act was already written and ready to be implemented long before. All they needed was an excuse. And then against all reason they went into Afghanistan to remove the Taliban.
Top general Wesley Clark even has stated publicly many times that he was informed and quite disturbed of the plan to invade Iraq BEFORE USA even had troops in Afghanistan.