Yes, whatsapp messages be subpoenaed but that is rare to occur
Since most service providers simply keep an archive of the phone numbers that sent and received texts, rather than the actual communications themselves, subpoenaing text messages is typically not an option. As a result, communication between two people is simple, however occasionally the provider may not have access to even that information. Additionally, the existence of a communication thread does not automatically establish misbehaviour.
Since the text needs to be validated, success in this field is uncommon. One of three events must occur for a text to be considered authentic:
1) The alleged offender acknowledges sending the text
2) A witness attests to having witnessed the message's creation.
3)We need to demonstrate response authentication.
As you may expect, each one of these three evidences could be impossible To occur .