This is not a big deal, but among the list of differences between LispReader and tools.reader behavior, this one seems a bit odd. \xHH isn't supported in EDN, nor in Clojure, and anything that can be specified with \xHH can be specified as \u00HH or in octal.
Patch trdr-21-v1.patch dated Jan 15 2015 removes \xHH from implementation code for regular reader, EDN reader, unit tests, and documentation.