That's a good question there Anthony. You absolutely don't need Redux. In fact, I would recommend you don't use it and begin with vanilla React.
For side projects, the most important part is to hack up functionalities quickly. Adding Redux will provide some resistance to it. Just sticking to ReactJS with minimal supporting toolset at first will help you get the app up and running quickly.
If/When you reach a point where you feel that the app is getting complex. You can start refactoring and reorganising the code. That's the best time to think about adding Redux.
Although, there is a situation when using Redux would be any good– if you already know it well and using it won't slow you down.
Good luck for your side project and keep hacking. Cheers!