Thanks everyone for responding to my call yesterday and Friday. I see I even brought out some people who normally just keep quiet on this board. I'll update more tomorrow, but I did want to say that the problem with DD9 is perhaps bigger than I initially portrayed. When she is here, it is truly like my ex has entered the house...secret agent daughter. And her psychotic mom (yes, I obviously have a history of marrying women who are "special") encourages this, according to her brothers.
We did have a talk, and I wasn't portraying ex-W as a bad person to DD9, just that it is important to exercise discretion when talking to EACH parent about what is going on in the other parent's life. I used the "it's none of my business" line, and did some role playing, like asking DD9 if my ex and her sometimes-boyfriend were dating. I told her it's none of my business, and then used another example of something that went on at my house that was none of my ex's biz. I also said that each of us did have business knowing if anything abusive was going on at the other house, and did some more examples/roleplaying.
DD9 said she missed the "old" W, who used to be so relaxed and fun. And I reported this to W, who admitted as much.
A lot more happened but it will have to wait until tomorrow. Things are settling down, though.