So what do you do in a ranked game with

Umm, that's kinda important to put in the description of your post :x It depends on if they have other ranged champs on their team or other knockups; if not then your team has seige power over them and should siege accordingly. If they do then treat it as a normal team with just the champ positions swapped.

Worse thing that the adc can do is respect Yasuo too much and let him free farm because they're scared of him when he doesn't have items yet. That completely depends on the adc type though, as some will harass so much that they'll miss cs and become useless themselves (thus defeating the purpose of zoning the Yasuo off of cs)