Heya! The video from 9:25 covers most of whats in the course at the moment.
And this blogpost has a roadmap for much of the content although all the dates are now wrong, but it does show the intended content at least: https://bramwell.itch.io/godot-4-beginners/devlog/362144/transitioning-to-gdscri...Unfortunately I don't have any immediate plans to cover C# as I don't have any personal experience with the language - that could change if I see lots of demand for it though :)