An IP address by itself isn't going to let you dox users unless you have access to the databases that map these to the subscriber accounts. Typically, you would need to be an ISP or law enforcement to do this, but you can also purchase this information from a data broker if you know what you're doing.

With that said, there is absolutely nothing stopping the instance operator from getting your IP address. You're connecting to his or her computer which they own, so they can easily see where you're connecting from.