Hello there, how is life on the farm? To answer your question, for less important events for kilt day wear then no, I don't think it matters one jot if the jacket and waist coat match. I think it not unreasonable for them to match as the importance of the occasion rises though.

It is not usual to see with the kilt those wonderful, red, or, creamy yellow, or my favorite creamy yellow with a tattersall type check waist coats seen out on the hunting(horses and hounds) field, or at market, like "down south" though.