I find on
downloadnew.org/drivers/scanner-camera/visioneer-onetouch-9520-driver-88423.html\
that
your scanner does work on linux and Unix as well as every windows
since
3.1. Unlike windows, Linux does not need drivers for most peripherals - they
are built in. Most manufacturers only supply drivers for the big market,
i.e. Windows, but that doesn't mean they won't work under linux. I don't
have your model but the two I have tried just work - without drivers - Canon
MP150 (built into a printer) and Mustek 1200 CUB (an old off-brand). Don't
give up on it too soon...

Have you tried installing "sane"? It is listed as "xsane" in the
repositories. It works with almost all twain compatible scanners, and that
includes all scanners made in the last 10 years. Just search for it in the
software manager or use Synaptic.

That name is an acronym for "scanners are now easy" and it is so much easier
than using them in windows.