My kid (9yo) had seen a couple of Roadrunner cartoons on Youtube, no more than that. e.g. I don't think he's ever seen a Sylvester-Tweety cartoon. It didn't matter, he enjoyed the movie a lot. Beyond the very basics of Coyote and Roadrunner, which everyone picks up very quickly- and if you don't they do a great modern version in the opening minutes to bring you up to speed- the movie doesn't need deep knowledge of the WB cartoon universe. It's not like the MCU that way.

And the fact that it reinforced a message his mom and I have been trying to teach him (about the importance of not letting failure keep you from trying again) was a bonus for us.