One of many factors.
Other equally important factors were Clintons move to make high credit risk, low income individuals homeowners, in many cases forcing banks to give mortgages to these people.
De regulation of the banking system.
A greater degree of interconectiveness in the world through globalisation.
The normal boom bust cycle didn't happen. We had boom boom followed by bust bust.
There's a move to blame individuals. However major cock ups tend to be a perfect storm of several factors acting independently but interacting at the same time.