Naturally the catalog is intended to be loaded either when a kedro jupyter notebook is loaded or a kedro project is run. But is there a way to load the catalog in a python script?

https://docs.kedro.org/en/stable/notebooks_and_ipython/notebook-example/add_kedro_to_a_notebook.html#use-kedro-configuration This section might work for you. Even though it's in the notebook section, this talks about using the various kedro components through code so it should be applicable to you.

exactly, everything that we show there should be possible from a script as well