Ah ha! I think we are onto something here! It looks like your installation of QIIME 2 is incomplete --- perhaps there was a network interruption, or anaconda.org (the service behind conda) experienced some kind of outage or issue. Either way, we should be able to clean things up by running a few commands, and then you should be able to reinstall QIIME 2 (fingers crossed!).
To clean up:
$ conda env remove -n qiime2-2017.9
$ conda clean -y --all
$ conda update conda
Then, head on over to the docs and follow the installation instructions (just like you did before!), and hopefully things will go better for you this time. Please keep us posted! 