Can’t say I agree with this – it makes sense to have it blow away weather and hazards that can be blown away. Making it do more than that feels like trying to rejigger a tool for a job it wasn’t meant for – just because it can be done doesn’t mean it should be done; that’s best left to something else, whether it exists already or just hasn’t been made yet 
Outside of that, we ought to make it so Cloud Nine holds effect even if a weather ability pokemon spawns afterwards.