Googling for the web browser options online, it seems Links[1] and Abaco[2] are the best options right now. There are others listed in Wikipedia[3].
I wonder if there's someone out there that has put in the effort to improve their Plan9 environment. I wonder how difficult it might be to port something like Chromium, Firefox, or Webkit to Plan9. Maybe it's not as tremendously difficult as I imagine it, but maybe I'm dreaming thinking this.
[1] https://en.wikipedia.org/wiki/Links_(web_browser)
[2] https://en.wikipedia.org/wiki/Abaco_(web_browser)
[3] https://en.wikipedia.org/wiki/List_of_Plan_9_programs#Web_br...