You cannot burn DVD9 in DVDWS2, but you should not try anyway. Even with DVD5 (SL) media, Ulead DVDWS2 was a terrible burner. Use Imgburn to burn.
I author DVD9 all the time.
There's nothing special in DVDWS2 that says "make DVD9", as it was aimed at high-end consumer, and was released at a time when DVD9 DVD+R DL was still a sci-fi tech fantasy.
Remember, there are guides and other topics for DVDWS at www.digitalFAQ.com
in the forum.