In answer to the thread's question, yes it was. Who did the conspiring is what is open to question. But it was a conspiracy, that then turned into action. Theory and planning converted into practice.
The official story is a fabrication.
LIHOP is very difficult to believe, far far too many people required to be in on the act.
Staggering incompetence by the biggest empire the world's ever seen seems too far out to accept. And if it was this, then you sure would have expected a few people to have been brought to book for their irresponsibility in protecting america.
No, the most likely scenario is MIHOP. Only those members of PNAC need have been involved. A quiet word with obl or any other CIA operative out there in saudi/pakistan/afghanistan and just let them all get on with the whole plan and execution of the plan. No missiles needed, no explosives, none of all that stuff that is termed under 'conspiracy guff'.