DVD-9 is a dual layer DVD. Your DVD drive must support dual layer burning
in order to use it. The disc you are trying to copy has more data than will
fit on a single DVD. If your burner is not a dual layer enabled burner,
then you will have to use software to split the DVD among more than one DVD,
and you will lose the menus and extras because they are no longer on a
single DVD.
There is software that will compress the DVD enough to fit on a single DVD,
but the results are less than perfect.
FWIW, if you are trying to copy a commercial DVD, you cannot do it unless
you have software that will defeat the copy protection encoded on the disc.
The Supreme Court has ruled that using *ANY* software to defeat copyright
protection on *ANY* DVD is a federal offense, punishable by both fines and
jail time. While it is unlikely that they will come knocking on your door
for copying a single DVD, you should at least be aware that in copying a
protected disc you are in fact breaking the law.
Bobby