acpitool software package provides command line ACPI client, 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 acpitool
acpitool is installed in your system.
Make ensure the acpitool package were installed using the commands given below,
$ sudo dpkg-query -l | grep acpitool *
You will get with acpitool package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Utilities |
| Package | acpitool |
| Version | 0.5.1-4+b3 [amd64], 0.5.1-4+b2 |
| Description | command line ACPI client |
| Sub Section | Utils |