No, it isn't, but there's a specific reason for this. Apple requires that any application that gets distributed via the App Store is sandboxed. This is perfect for casual videogames, as it restricts the level of access that an application has to parts of the operating system. However, for an advanced tool like CCleaner for Mac, it's problematic and doesn't allow our app to do its job properly.
What does this mean for you?
Following the Apple requirement introduced in July 2012, we can no longer distribute CCleaner for Mac via the App Store.
You can download the latest version of CCleaner for Mac from https://www.ccleaner.com/ccleaner-mac