In its entirety, the phrase “the whole kit and caboodle” is American; it is a somewhat more refined expression than the earlier, “the whole kit and bilin’.”
Both forms mean lock, stock, and barrel; the whole lot, omitting nothing. But “the whole kit” is plain English, the entire outfit; the whole lot, either of things or persons.
“Bilin’,” of course, was corrupted from “boiling,” which meant a seething mass, especially of persons; so “the whole kit and bilin’ ” originally meant the entire group of people and their equipment. Later it was limited to define just all the people in a group.
But along with the common expression, “the whole kit and bilin’,” there was a more refined American phrase, “the whole kit and boodle,” for “boodle” was apparently Americanized from the Dutch word boedel, property, estate, goods. And just because we like to have alliteration in our speech, someone tried to put a “k” before “boodle,” giving us, “the whole kit and caboodle.”
By the way, it was this same Dutch word, corrupted to “boodle” also, that was later used in a sinister sense to mean money, money acquired by graft or bribery.