9wm software package provides X11 window manager inspired by Plan 9s rio, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install 9wm
9wm is installed in your system.
Make ensure the 9wm package were installed using the commands given below,
$ sudo dpkg-query -l | grep 9wm *
You will get with 9wm package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | X Window System software |
| Package | 9wm |
| Version | 1.3.9-1 |
| Description | X11 window manager inspired by Plan 9s rio |
| Sub Section | x11 |