Here's Bill Clinton's contribution, years before Bush took office, back in the late 90's.
Ameriquest, a subprime lender who's slogan was "proud sponsor of the American Dream," became the first subprime lender to have its loans financed by Fannie Mae (the Federal National Mortgage Association). The lender that pioneered "no-document" loans eventually settled for $325 million with several attorneys general over charges of predatory lending, in 2006. Ameriquest closed in 2008.
Sub-prime lending was already happening before Bush showed up. Like I said, the bust was coming. The lending practices in place from the late 1990's until the crash only help build the bubble and delay the cyclical housing crash. Did it make it worse? Sure. Did it cause the crash? No. And even your post states Bush saw the bust coming and tried to mitigate the circumstances "spending years pushing Congress to tighten regulation". But you don't blame Clinton for loosening the regulations and allowing sub-prime lending just like you don't credit Bush with trying to help. Like I said in another post, most people, such as yourself, have their ideology in place and try to structure the facts to fit their narrative.