Hello. You refer to Christian faith, but then tried to apply it outside of a Christian context. There is lots of evidence that the Bible is the infallible, inspired Word of God, but faith was never intended to be part of such evidence. Faith is believing that something is so, even though your eyes do not see it to be so, simply because God said so. Faith of the Bible always points to Jesus Christ, which, to answer your question, differenciates itself from the 9/11 hijackers who did not have faith in Jesus Christ.
Faith is taking God for His Word before He gives evidence of its fruition. Faith is understanding that God's Word is Truth and Truth only originates from the mind of God, of which He has expressed via His Word, i.e., the Bible.
God often tests our faith by giving our eyes apparent contradictions to His Word. Without faith, it is impossible to please Him. The purpose of Him testing our faith is that our faith gets strengthened when we pass the test. He disciplines us when we fail the test. His discipline matures us.
Faith is not a blind hope for the unknown; rather, it is a concrete "substance" of confidence and an invisible assurance of God/Jesus' reality.
Jesus often told His disciples, "Oh, ye of little faith." There are degrees of faith. Great faith is accomplished when we act like God is telling the truth even though the circumstances appear otherwise. God rewards great faith. Jesus said that mustard-seed faith is capable of moving mountains.
Finally, it is important to understand that faith in anything other than Jesus Christ is not the faith that the Bible refers to. The source of true faith is Jesus Christ. Faith devoid of Christ voids faith.