Hi, author here. I haven't tested it on ClojureScript yet, but since core.async is supported by CLJS I don't see the reason why it wouldn't work there as well.
If it doesn't, let me know on Github and I'll look into it! I don't have any experience with CLJS, but I'm interested in learning so it'd be a good excuse.
I submitted a pull request which sets up the project to use cljx to work in both Clojure and ClojureScript.
ETA: Just realized that <!! and >!! aren't available in ClojureScript, so it needs some more work to be complete, but the pull request should help you get set up to develop for both.