A key generator (or "keygen") is a piece of software designed to create unauthorized serial numbers for games. While they were common in the mid-2000s, using them in the modern era poses several significant risks:
Use community-made widescreen fixes to ensure the game doesn't look stretched on 1080p or 4K monitors.
Right-click the .exe and set it to run in Windows XP (Service Pack 3) mode.
If you do manage to install the game, you may run into compatibility issues on modern hardware. To get "high quality" performance:
Use tools like DS4Windows or Steam’s controller configuration to get modern Xbox or PlayStation controllers working with the older input system.
If you are looking to get back on the ice, here is everything you need to know about the safety of key generators and the legitimate ways to play NHL 09 today. The Reality of Key Generators
Since the game is no longer sold on digital storefronts like Steam or Origin, the most reliable way to get a valid key is to purchase a used physical copy from sites like eBay or local retro game stores.