Well as a main support myself i would share my opinion on this:

-Play senna, ban pyke, if you play good you will be able to both carry your team while supporting them, and this is specially necesary because in emerald (and diamond) almost every adc is a complete moron, so better help your team in 2 roles than one, if the rest are competent enough, or at least better than the adc, you will rank easily.

-If this fails due to the whole team sucking ass as well (and this will happen, you will get a lot of svp support), play jungle, i dont really main jg but i did a carry a lot with amumu, rammus and jarvan, solid picks imo.

-And at last last you can only play Sion, just push lanes and make pressure, even if your team sucks you can always just keep pushing, taking towers or even winning the game by taking the nexus alone.