Hi Mark, and welcome. The following thread is a good guide to getting your SDT 9000 to play ball with audio DAT playback...
http://theartofsound.net/forum/showthread.php?t=5329
If you have a Mac, you can also try DATXtract
http://pdicamillo.org/~peter/datxtract/
As far as DAT2WAV is concerned, once you've worked out which SCSI address your drive is on, it's just a matter of following the instructions in the Info file that comes with the executable. Familiarity with DOS helps though.
What kind of stuff do you listen to Mark, and what does the rest of your system look like?
PS. I'll move this to Digital Expressions later...