As Keith notes, this is poison to vote against. Ultimately nothing comes from the legislation being passed. However, it does look bad and technically opens America up to litigation (say hello to victims of drone attacks).
This seems like a good idea to me. If governments engage in illegal actions then the victims of those actions should be entitled to compensation.
They were compensated at least a few million a piece.
The question becomes how do you sue Saudi Arabia or individuals in Saudi Arabia? You'd need access to intel and in depth information via warrants (good luck getting anything from the CIA). You can't just cite the 9/11 Report and say Saudi Arabia owes us money. It gets harder to sue individuals. It'd cost a fortune to pull off an investigation, if it could even be had. Saudi Arabia will not view any lawsuit with anything but a face palm.