Installation of new tools does not proceed past "cloning." I'm using galaxy version 18.09. There is no entry for this when I select "view error log."
The 18.09 is an unreleased development version of Galaxy, the current release is 18.05 https://docs.galaxyproject.org/en/master/releases/index.html
That said it should work. Do you see anything suspicious in the Galaxy's log?