Charlee just saw this post! :)
VERY nice machine!! That cabinet is to die for! :) Your machine was made prior to 1906 when W&W sold out to Singer.
Clean it gently, I'd use sewing machine oil, and use a good non-abrasive car wax to polish her up....then use her like there's no tomorrow! :) FUN machine to sew on!
The downside to a 9W is that the original needles can be hard to come by, but there are new needles I've seen posted on ebay that are supposed to fit these machines...I haven't tried them yet.
I downloaded a manual for mine...I'll see if I can find it for you when I get home from work tonite, unless you have one already.
***EDIT***
I just found on sewmuse.co.uk that the W9 machines were made from 1887 to 1905 by W&W, and after that by Singer as the Singer 9W.