Indeed, it's a half-truth. He was trained, funded and supported by the CIA in the 1979-mid 1980s period, as part of an illegal project for destabilizing governments that the Reagan-administration didn't like, which also included support to the contras, mujaheddeen and taliban.
The program was officially discontinued somewhere in the late 1980s (just before Bush Sr. succeeded Reagan, who by this time was so affected by Alzheimer's that in all honesty he can't be held responsible for his second term), but likely still continues. It is very unlikely that Bin Laden had any support after the early 1990s, though, as it was perfectly clear by that time that he was violent, megalomaniac and anti-American (only the latter was perceived as a problem, of course). The Clinton-administration was working hard on cutting off Bin Laden's funds and support from other sources by 1995 at the latest, but Bush Jr., immediately upon becoming president, discontinued the operations as they were 'tainted', because they were started by a democratic administration. In that sense, the Bush-administration can be held responsible for 9/11, but in that sense alone.
Not Plutus but Apollo rules Parnassus