For the put options:
http://www.911myths.com/html/put_options.html
American airlines was falling like a rock before then, many believed it would fall farther, therefore, they placed put options on it.
For the rotation:
the side that collapsed first stopped supporting the upper building, so it fell, since the upper stories were still whole, it rotated slightly, but the rest of the floors at the impact gave way, and the upper part smashed down, the rotation speed was minimal, and the speed down was much greater, that’s why it did not rotate very much at all. Further more, the upper floors broke because of the impact with the floors below the plane impact, the floors are designed to stay level, as the impacted on an angle, they are not designed to support that kind of load.