The basic Photoshop only plan is all you need. The Photography plan includes Lightroom, which is for organizing your photos and working with Camer RAW images; if you are not a photographer or don't need to organize and sync all your photos then you probably don't need it. The full Creative Cloud plan includes every application that Adobe makes; if you're only interested in Photoshop then there's no need to pay for that level (though you may find other applications you like in there).
Do you mean that you will first scan theses photos?
In this case a basic plan is enough. What matters most is your computer. Must be a good one with GPU and enough Ram, and a good internet connection. You should use features like Photoshop Neural filters offer.