The 9/11 attacks were neither elaborate nor involved sophisticated weapons. They were simple and well co-ordinated. The only expenditure was the lives of 19 men willing to committ suicide. An everyday form of transport was used to maximum effect. No guns, bombs or other weapons were used apart from the box-cutters used to overrun the aircraft. Simplicity itself.
The MO which the terrorists use in Israel is simple, crude bombs detonated in areas where maximum damage will ensue.
The bin Ladens of this world are blood-thirsty men. He has no qualms about shedding blood on a grand scale. I have zero belief in the theory that he is waiting for the green light from Islamic scholars. This is propaganda designed to give a theological face and justification to the mayhem he has perpetrated and to cover the fact that right now, he's living in a hole in the ground and only comes out at night.
You said it better than I. These are not superhuman people, just thugs with big ideas. And now bluster.