I have Chapter 81 of Angels and Demons right here infront of me and it doesn't mention any U.S. President for that matter. Perhaps we have different editions...
And this is the only mention I remember of U.S Presidents...
"Many members of the Illuminati came to high ranks of power within the Freemasons and the free world. They grew more powerful across the world and many famous, god-fearing men like George Washington and Ben Franklin, well known Masons, were also unknowingly Illuminati."
And remember the important thing... due to the Catholic Churches' misuse of the word shaitan meaning "satan" in Islamic, the Illuminati were wrongly portrayed as a Satanic cult. In reality they were a collection of rejected scientists made out to be monsters by the web of lies created by the conniving Catholic Church.