Here's my task nine essay. It took five minutes, is 120 words long, and has no grammar mistakes.
Score: 4.0.
I guess when ETS says, "An effective response will contain at least 100 words," their definition of "effective" is 4.0.
The global average TOEFL speaking score is 19. The Japan average score is 15. For our students who take 4+ months of classes, the average top TOEFL speaking score is 23. Why? Because they don't use templates! If you have a clear voice and practice regularly, you should get 23 consistently too.