May I add my comments to the excellent answers from the other members?
I checked one of my favorite books *** and found this:
"We can use 'would rather' to say that one person would prefer another ... to do something. We use a special structure with a past tense."
WOULD RATHER + SUBJECT + PAST TENSE
Here is one example from that book:
"I would rather you came next weekend."
*** The book says that "a present tense is sometimes used in this structure, but this is unusual."
I guess that some teachers would prefer that your sentence read:
I would rather that we waitED until tomorrow.
*** You may already have this book. It is extremely popular with both students and teachers: Practical English Usage by Mr. Michael Swan. (I have the 1995 edition.)