I don't think anyone you'll hear from on the forum is qualified to give you legal advice in this regard.
To answer the technical question of whether or not CCleaner can pose a risk, the answer is yes. Anything that can modify the registry can break it, if used incorrectly. CCleaner is much "safer" than most other registry cleaners in this regard, but it has been known to bork a system every once-in-a-while (though this is most often the result of overzealous cleaning)