For win I still have problems with self compiled QT5.9 (because of the boost 1.7) so I used QT5.6
I would suggest using QT5.9. I'll update it when I get it working (I did see your pull request test)
I could also package directly from your win QT5.9 Conda Win build in a new conda env. This might be a good exercise, after this it should be easy to add it to the Travis weekly Conda builds.