cinnamon-core software package provides Cinnamon desktop environment - essential components, 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 cinnamon-core
cinnamon-core is installed in your system.
Make ensure the cinnamon-core package were installed using the commands given below,
$ sudo dpkg-query -l | grep cinnamon-core *
You will get with cinnamon-core package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Meta packages |
| Package | cinnamon-core |
| Version | 3.0.1 |
| Description | Cinnamon desktop environment - essential components |
| Sub Section | Meta packages |