Yes, All Box prime 9 chains have standard external geometry that will work with most existing 9 speed drivetrains.
No, Box Prime 9 chains are compatible with most 11-speed wide narrow chainrings but there are some chainrings that can result in poor performance. We recommend the following 11 speed wide/narrow chainrings for best performance, Wolftooth Components, Raceface, One Up Components, Absolute Black.
We suggest removing the chain from the bike and using a soft bristle brush or rag with soapy water or a mild de-greaser. We do not recommend pressure washing, strong solvents or de-greasers as they could degrade the surface coating.