How did I catch a level 8 Spewpa in the wild, one level before it should evolve?

Question

I caught a level 8 spewpa but then found out I need to be level 9 for scatterbug to evolve. How is this possible?

Comments

Because the game designers wanted it to be possible

Answer 1

In all the areas you can get Spewpa in Scarlet and Violet (South Province 1, 4, and 5) you can find Spewpa ranging from level 8 to level 20.
As to why "impossible" Pokemon exist, just look at Lance and his Dragonites' levels. They're all below what is technically "possible" cause game designers can be lazy sometimes and forget which levels Pokemon evolve.