There is plenty of blame to go around. Even Bush.
President Bush Signs American Dream Downpayment Act of 2003
https://georgewbush-whitehouse.archives.gov/news/releases/2003/12/20031216-9.html
He did encourage home ownership, which is generally a good thing. He did not make any policies that had any significant impact on that crash. That was a long-time coming and had much more to do with policies set in the late 90s. I seriously doubt this had much of an impact. even if all 40,000 people defaulted, that would be a drop in the bucket. I definitely would have preferred he did some things differently, but blaming him for that downturn is silly. That’s like giving Obama credit for the growth the past 6 years.