If you have already played the Dragon in the past and you feel that you have a pretty good grasp of Dragon  theme's and motifs, then you probably don't need a book like WWTSD2. Though I found Ward's explanations to be invaluable, the unfortunate fact that the ...Qa5 system pretty much appears to be refuted makes the bulk of the book pretty much worthless now. In addition, the fact that 9. O-O-O Nxd4 is under intense scrutiny and 9...Bd7 is pretty much refuted makes the 9. O-O-O Yugoslav Chapter pretty much lacking in theoretical value. So unless you really need help against the Classical, Levenfish, or 9. g4 Yugoslav Attack, I don't see the need for you to spend the money. Instead, a subscription to Ward's Dragons section on ChessPublishing.com is probably much more worthwhile.

With regard to which lines to play, 9...d5 is probably the safest choice against 9. O-O-O as it certainly doesn't seem as though it will "soon be refuted." Against 9. Bc4, the old lines with ...Rc8 but without ...h5 still seem to be pretty solid for Black. However, if you desire something a little more active, the Chinese Variation is still quite offbeat and an equally good choice. 9. g4 can still be met with the ...Nxd4, Be6 system and other than that you should have no real problems to speak of that cannot be answered by something like ECO or NCO.