That Osama was hiding there. Which he was, at the time. And that he had carried out 9/11. Which he did.
The Irag and Afghanistan wars were not the same. Practically everyone supported the US in Afghanistan. Practically no one followed the US into Iraq.
American GEOINT, MASINT, SIGINT and TECHINT are likely the best in the world. American HUMINT, OSINT and--somewhat paradoxically--FININT are atrocious. Unfortunately, we frequently ascribe confidence intervals to our clandestine services based on experience with e.g. the NRO.