I wouldn't have said anything to the tardy Mom. And she would have gotten a glare from me. Not so much a death glare but a 'I'm am clenching my teeth and biting my tongue to avoid saying anything I shouldn't' glare. Getting the 'apology' she gave? Then she'd get the death glare. Or a tongue lashing. Or both.
OP, I think you did the correct thing in talking to the director. And in future, if you or your husband are unable to drive, I think it is perfectly reasonable to let them know that you do not want your child in Ms. Tardy's vehicle and if they are unable to arrange that, let you know so that you may make alternate arrangements.