Could this also be "s/he has a physics class tomorrow," or would that need "onun" to specify?
Hmm. Yes, it could also mean that. Good job!
It's now an accepted alternative.
He's is he is, I have never heard it as he has. Why is "physics class is tomorrow" incorrect. I don't she he in this sentence
"(The) physics class is tomorrow." can't be the right translation for the Turkish sentence above because of the presence of "var." Many hard knocks have made it clear that if var ends the sentence, and if a possessive construct doesn't come before it, "there is" had better be in your translation or face a dinging!
Yarın fizik dersi var. (However, "There is physics class tomorrow" was not accepted as a translation for "Yarın fizik dersi var" because, I guess, not everyone would consider that a grammatically correct sentence in English.)