Canoscan 9000 Mark II is using sane-pixma backend, so editing /etc/sane.d/canon-dr.conf
is wrong.
See SANE Supported Scanners database for more info.
WARNING: Following is NOT The Right Way™ to do things!
I got mine to work by updating my udev, libsane and libusb from Debian's Testing version. I don't know, if some of them wasn't necessary.
Like this in terminal:
$ sudo echo "deb <mirror> testing main contrib non-free" >> /etc/apt/sources.list
# Sources are not necessary but here they are if wanted
$ sudo echo "deb-src <mirror> testing main contrib non-free" >> /etc/apt/sources.list
$ sudo apt-key --keyserver keyserver.ubuntu.com --recv-keys 46925553
$ sudo apt-get update
$ sudo apt-get install udev libsane libusb-1.0-0
Debians <mirror>'s.
Do NOT use atp-get upgrade, because it's about The Best Way™ to destroy your Ubuntu installation. Do remember to remove or comment out those repositories from /etc/apt/sources.list afterwards.
$ sudo <put your preferred text editor here> /etc/apt/sources.list
$ sudo apt-get update