I'am afraid that this will crash. It sounds as if you have build pyclutter against gl but clutter will use gles - did you try to run something on the target? My suggetion is to wait for a later version
of pyclutter - this worked fine for clutter-gst :-)

I ran clutter with gl forced.  Oh the later version of clutter-gst worked for gles2 ?
Although I was successful getting the clutter-tests to build, pack, have menu entries (Entry 'other' ??) and RUN I am not happy: The test-applications are far from stable, have pixel errors,
some crash immediately...

I don't have a display yet. Which display are you using?