Just to follow-up since i'm the one with the quiet teacher pleaser. His preschool teacher actually did notice and was the first to say that he would have to be accelerated at some point in school. But then there were only 8 kids in preschool, compared with 24 in kindy. But the good news is that the principal is aware, and you are aware, and you will go to bat for your kid.
It does sound like MAP tests you're describing. I think they are really fabulous tests, but like someone else said, it all depends on how the school uses the results. And if you have an outlier, you may still be in a bit of a pickle because there may not be anyone with similar scores. Then you find your kiddo in a group of one...
If you still have the principal's ear now, or when school starts, you may want to ask more about what they do once they get the results, and what they do if your child's results are more like kids a grade or two ahead. Do they have any block scheduling, e.g., so your child can go to 1st for reading or 2nd for math when the other kids are doing their kindy reading and math? Just a thought.