Sounds like a free upgrade to me, install CPU-Z or even open up taskmanager and see if either of those also show you have a 9600K. I wouldn't really worry about it though, as long as it works and all cores/thread are detected and the core clocks are stable -then there's nothing wrong eh? Now you have bragging rights that you have 9th gen ( ͡° ͜ʖ ͡°).