Hobby use. Though I do have a little nuc at work running 9front to write small bits of automation (IEC 61131-3, ST) and a Basic dialect of CNC RS-274 G code in acme and a little Sam here and there. I'm slowly learning it. I also write a little c code as the plan 9 c library and tooling is really nice. And I love the concurrency library, thread(2). I access the little server via drawterm from both a Linux machine and a Windows 10 machine. I can sit at either computer and have access to the same user files, configuration, etc. And drawterm gives the plan 9 session access to the host (terminal in this case) resources including the TCP stack (you can do really cool routing and tunneling tricks with this method)

I highly recommend giving it a look (I highly recommend 9front), and read nemo's intro.