If you are new to using a snapshot of clojure (like me), you can find some helpful information here: http://dev.clojure.org/display/community/Maven+Settings+and+...
tl;dr
In a Leiningen project.clj file:
:repositories {"sonatype-oss-public" "https://oss.sonatype.org/content/groups/public/"}
Also, in that lein project file, reference clojure as
[org.clojure/clojure "1.9.0-master-SNAPSHOT"] (1.9.0 being the dev head right now)