Reading through them, it is not definitive (i.e. "beyond reasonable doubt") that there were direct connections between the hijackers and Saudi government, but I think anyone who reads these and thinks no one in top levels of Saudi government knew about the planned attacks is being willfully naive.
http://intelligence.house.gov/sites/intelligence.house.gov/files/documents/declasspart4.pdf
http://intelligence.house.gov/sites/intelligence.house.gov/files/documents/declasspart4.pdf
