is CleanMyMac X safe

Never install any app that claims to "tune up", "speed up" or "clean up" your Mac. These apps exist for one reason: to separate the unwary and inexperienced user from their hard-earned money. At best they do very little, at worst, they can damage your OS installation and cause far more problems than they "solve".

cleanmymac is one of the worst things you could install. if you're worried about security or keeping your mac clean, please read Effective defenses against malware and other threats - Apple Community. it's a long article, but well worth your time to read.

Search these communities for the hundreds/thousands of posts where third party apps have caused problems.