I looked through like 25 pages and didn't see this asked, so if it has already I apologize. Do coaches increase ratings yearly or do they stay the same all the time? If they do, how is it decided (record/stats)?

Clicking the coach's name will open their player card. Selecting 'view' will then open their player page. From there you can select the 'Progress' tab to see when and by how much they've increased since their first gen date.

To more specifically answer your question, coaches can change in rating at any time of the season. As far as I know, just as with player development their volatility (how aggressively they go up and down) and their overall growth direction (positive or negative) is seeded at 'birth', and is not impacted by their records.

Thanks for your help

Keep in mind that even newly generated coaches can get worse than they currently are as well. Not every coach gets better. Also coaches will start to regress when they get old.