Apple Watch is one of the many devices which can be located in Find My, if that is what you mean by finding that your child has arrived safely.
If the watch is signed into your Apple ID account it will already be visible in any other device you have which is also signed in to your account.
In addition, Family Sharing will show you family member's devices signed into THEIR account.
An Apple Watch is a lot to risk if you are having it go off to school. If you are thinking of a device less expensive device to use you might want to consider an AirTag.
Alternatively, the watch can send you a message from the school, but again if it is signed into your account Family Sharing is not required.