The White House said in January that it was reviewing the file, said that it had set no timetable for the conclusions of its deliberations.
Some families of 9/11 victims have campaigned for several years for the declassification of the 28 pages, supported by Mr Graham who has now enlisted the high-profile Mr Paul to his cause.
"Information revealed over the years does raise questions about [Saudi Arabia's] support, or whether their support might have been supportive to these Al Qaeda terrorists," Mr Paul said at the press conference in Washington this week.
"We cannot let page after page of blanked-out documents be obscured behind a veil, leading these families to wonder if there is additional information surrounding these horrible acts."
Fifteen of the 19 hijackers were from Saudi Arabia, but previous investigations always failed to find a formal link between the country and the terrorist attack, which killed 2,996 people.
Many victims groups believe the full extent of Saudi involvement in 9/11 has long been covered up by both the Obama and Bush administrations to protect US-Saudi relations.
Terry Strada, who leads 9/11 Families and Survivors United For Justice Against Terrorism, said that the supposed Saudi funding link was not a surprise.
"Nearly every significant element that led to the attacks of Sept. 11 points to Saudi Arabia," he said. "Money is the lifeblood of terrorism. Without money, 9/11 wouldn't have happened."
Earlier this year, the theory of Saudi involvement was given added impetus by fresh testimony from Zacarias Moussaoui, the so-called "twentieth hijacker" who had taken flying lessons but was arrested weeks before the September 11 attacks - although was later disowned by Osama bin Laden.
In a plea to a New York court released last February, Moussaoui said that senior members of the Saudi royal family were major al-Qaeda donors and were intimately involved with Osama bin Laden's terror network in the 1990s.
He named Prince Turki al-Faisal, then the Saudi intelligence chief; Prince Bandar Bin Sultan, the longtime Saudi ambassador to the United States and Prince al-Waleed bin Talal, a prominent billionaire investor.
However the Saudi Embassy dismissed Moussaoui - who was diagnosed as a paranoid schizophrenic - as "a deranged criminal" trying to "get attention for himself and try to do what he could not do through acts of terrorism - to undermine Saudi-US relations".