Kindergarten is supposed to be the fun year. Darn. Hugs.
The squeaky wheel gets the oil.
Let them all know that you're not going to have an unpleasant whole year in Kindergarten sour your kids attitude on school in general. They're impressionable and it's their formative years.
FWIW, I wouldn't necessarily insist that they actually make sure he's learning much at this age, but I would insist that they prove to you that they'll find a way to make a positive first impression of school, learning, and education in your little boy's mind.
Tell them, "who am I going to believe, you or my lying eyes?" If you're Saying your kid's miserable and crying to you about it, tell them answering that he's happy does not change what you see. Tell them, "maybe you haven't seen it, but I'm letting you know it's there". Surely they won't call you a liar. And if they try to comfort you like a hysterical new mom, remember, this isn't the first two months of school where it's not unusual for kids to cry. This is the second half of the year. He should like Kindergarten by now. Kindergarten, of all things.

Remember my thoughts are just thoughts. My kid doesn't start school until next year.


Youth lives by personality, age lives by calculation. -- Aristotle on a calendar