agda-bin software package provides commandline interface to Agda, 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 agda-bin
agda-bin is installed in your system.
Make ensure the agda-bin package were installed using the commands given below,
$ sudo dpkg-query -l | grep agda-bin *
You will get with agda-bin package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Haskell |
| Package | agda-bin |
| Version | 2.5.1-2+b4 [s390x], 2.5.1-2+b3 |
| Description | commandline interface to Agda |
| Sub Section | Haskell |