Clearly without enhanced techniques, this information would not have been acquired, and another jet liner would have crashed into a building in LA.
So the questions remains... would this be acceptable to everyone?
Let's spin the question around. In 1993, after the first terrorist attack on WTC they captured Ramzi Yousef. What if they had waterboarded him, and got information to the location of Mohammed Jamal Khalifa, thus 9/11 would never have happened.
Are you happy with the outcome of no waterboarding?
So far, this is all historical theoretical. Can you assume these situations will never happen again? If not, then what do you suggest we do?