I am just confused, the description says it’s 9 hours, but on the itch.io Jam page it says 7 days.

It's so you can pick your time when you can work on the game. The challenge is to have the total development time within 9 hours. It's the same principle regular Trijams work - 3 hours jam over a span of a weekend (72 hours). We used to have only 3 hour jams in the beginning at specific time, but a lot of people would have wanted to participate in this jam, but they couldn't make that time. Some people have free Saturday, some have Sunday. I hope it makes sense!

Keep in mind that planning and preparing builds doesn't count in the 9 (or usually 3) hour limit. It's just the development. How do we know you didn't go over the limit? Well, just say in the description you did. It's about being honest with yourself and about challenging yourself, working on gamedev skills even if you don't have the whole week, ( usually the whole weekend) free. Just making yourself do something and have some results. Those who participate regularly have made great progress in their planning and game design skills. :)