This is sunburn in the
plant world. The yellowing leaves will fall off, there's nothing to be done about that. The
plants themselves should have no major problems, and will put out new leaves. Some of the vine tips may die, too. It may take a year or more to look like nothing ever happened to it, but it will get there. I have a hoya that goes out in the summer and I have to wait until June when the
trees have leafed out so I have shade. And I live in cloudy, rainy, yucky New York! Florida sun may be too much for any hoya, and certainly hours of direct sun are! But don't worry, you didn't kill them. How long have you had them? What kind of hoya? How big are they?