"737 Max 9 - is that new? I thought 737 was one of the OG planes and I'm guessing Max 9 is like saying you've got an iPhone plus or whatever"
Sorry, I'm just joking. To be fair to the other poster they are relatively new and the aircraft themselves that crashed were very new at the time.
The max 7, 8, 9 are intended to replace the original 737s and then there's the 10. The different numbers are just the configuration of the planes.
They've been in production a decade though, so nobody would describe them as "new", especially since they've spent years in the spotlight. The other poster obviously just thought they were new and that's why the Warsaw plane being a max 8 was relevant but it's not, it's because of the heat they've had over the past 8 years. Some people refuse to set foot on one.