astropy-utils software package provides Command line tools from astropy, 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 astropy-utils
astropy-utils is installed in your system.
Make ensure the astropy-utils package were installed using the commands given below,
$ sudo dpkg-query -l | grep astropy-utils *
You will get with astropy-utils package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Python |
| Package | astropy-utils |
| Version | 1.2.1-1 |
| Description | Command line tools from astropy |
| Sub Section | Python |