It helps, and like most Ashampoo apps it's easy to use, but like most automatic photo adjusting apps, you can do better adjusting things manually. This kind of app is best used to batch process a collection of photos to save time. In a quick test it did improve color cast, though it didn't get it quite right -- subjectively I'd rate it ~80 out of 100. It came closer [~90] setting the black & white levels -- the darkest & lightest parts of the photo. It didn't seem to have any other effects, e.g., noise &/or sharpness, but color balance or cast & black & white levels are 2 of the most important adjustments you can make.
Installing Ashampoo Photo Optimizer 9 adds a [probably redundant] copy of the Microsoft C/C++ runtime files, the app's main folder in Program Files\, a folder in ProgramData\, and a folder in Users\ [UserName]\ AppData\ Local\. Besides the entries for the C/C++ runtime files, the registry gets 4 Ashampoo keys, which isn't bad at all, but then it hijacks the file associations for several image file types. From Ashampoo's perspective it makes it easier because double clicking an image automatically opens in Photo Optimizer, but they should give you the choice, since you may feel it's more useful to open images in Windows Photos for example.