The gurobi9_installer.py file is a simple script to install gurobi version 9 on a linux machine.
This script is simply the encoding of the instructions found on the official documentation.
To use it you have to download the archive containing Gurobi from the official website and then launch the script passing as an argument the path of where it was downloaded.
For example, if you want to install version 9.5.2:
$ python gurobi9_installer.py /home/user/Download/gurobi9.5.2_linux64.tar.gz Gurobi is installed in the /opt/gurobi9xx directory (xx depends on the version), and environment variables are added to the end of the .bashrc file.