Mobile? Wouldn't that be even harder?
On Android, there is the issue Clojure is still a bit fat and uses too much reflection during startup. ART might make it harder as it is a AOT native compiler.
On WP, there are currently no efforts for Java support, other than maybe via ikvm.net. Or Clojure-CLR.
However I tend not to like having layers between language and final execution target, as it increases debugging headaches.