Originally Posted by jswinden
Are double-layer DVDs used for movies officially released by major studios? If not then they are irrelevant to the discussion.
Yes, of course they are. It's only the most stripped down basic edition DVDs, or very short movies, that are on single layer discs.
That's why programs like DVD Shrink (going back a ways) and DVD Fab have functions to re-compress movies to 4.7GB, so that they can be copied onto one single-layer recordable DVD.
If the poster is doing a full disk rip, this could be the cause, though most of the disks in my collection have an actual size of closer to 7GB, so 9 is still pretty hard to explain.
Of course with silly settings, it's possible to inflate even the smallest video to 9GB.