So I have a crazy idea on how to get back into ranked as a sup main.
Trundle Support and Syndra so I can always build carry if it turns out I need to. Now I ask you to lay down the touches and pitchforks for now and listen to my reasoning. I'm silver, and as a support player I am almost 100% reliant on my team mates to make good calls in order to gain a lead. By picking supports that can at least wave clear I can always have the option to do things on my own. I have had numerous ADC's not know how to press an advantage. It sucks. So since I'm in such a low ELO and I know I can do better with a better team to support I'm a be crazy and play carry sups so I can pull myself up to at least Gold were I think I belong. At witch point I will go back to my Soraka's and Braum's.
for a carry support- she can actually function as a real support but is extremely effective as a carry as well. If you go aggressive in lane and can land your dark bindings consistently you will thrash low elo.
support you may run into the same issue... 
has enough sustain/damage on his own though to likely trade effectively, so that could definitely work for you. What I would really recommend though to compensate for poor adc's is 
. You get three forms of CC as well as bonus movespeed for both you and your carry. Max E and use it generously on your adc during lane phase. Tell them to try to trade a few auto's when they have it on. Your Q and R will protect you from all-ins or ganks. I found that even though she is not a carry, she has enough utility to make a whole team succeed (this is from playing her out of Bronze in Season 5).
would be a better pick for an AP support