This alleged link between the 9/11 terrorists and the Iraqi government is not credible. First, the 9/11 terrorists did not need the help of the Iraqi government. Second, terrorists are not going to discuss their plans in the open in a restaurant in Prague. It's quite credible, given all the failed but serious attempts to disprove it. For a number of reasons, it's quite likely that Saddam was informed of 9/11 before it happened. And, really, terrorists and spies operate frequently in the open. Information can be passed or transferred quite readily without an open conversation.
Perhaps you can explain why Atta would share the details of a top-secret terrorist act with an Iraqi government agent when he did not need his support.