The fantasy of an unstoppable "Xbox IP puller" that gives you god-like control over your rivals is exactly that—a fantasy. Real IP pulling requires:
that IP address to launch a DDoS attack, gain unauthorized access, or harass someone is illegal under computer crime laws in most jurisdictions. How to Protect Yourself
No legitimate software can pull an IP address from a Gamertag alone without a live connection. If a website promises you can "enter a Gamertag and get their IP instantly," it is almost certainly a scam designed to steal your own IP or infect your device with malware.