If your phone is not rooted then the Google Playstore is still there (your child must have just deleted the shortcut)... Look for it under the APPS menu and renable the shortcut
You can not delete or uninstall Google Play store because it is a system app. It can only get corrupted if tried to modify it through a program like lucky patcher or a custom patch that will overwrite phonesky.apk
Though if it's really just disabled. You can just start the service in the application manager.
I suggest hard reset/system reset your phone to clean its dalvik cache (which is probably the cause).
hi there..your kid might accidentally hide the application in your phone..
go to apps
press the right key then show hidden apps^_^