This is a question that I see asked a lot, and the answer is usually yes, that champion could be a viable support in most Elo ranges/leagues. There are three traits that make good supports, and not all supports have all of them, but most good supports will have at least two.
CROWD CONTROL. This is probably the most important thing to have. CC can be used to dive or to peel; in lane you are usually going to be using it to dive, and later you'll use it more to peel. CC is something that literally scales only with CDR, and most support items give some amount of CDR, so it's good for the support to have a lot of CC.
HIGH BASE DAMAGES/STATS. This is also something that scales really well with CDR, but it also scales with pen. In particular, your high base damages will make you able to output a lot of damage in lane, when base damages are much more relevant than scalings. Note that if you're playing a support for this trait alone, and you're unable to snowball your lane forward, you'll start to snowball back and become irrelevant very quickly.
ALLY BUFFS. Heals, shields, invulnerability, speed boosts, stat boosts. They let your team fight better both during and after laning. They can help your ADC kite better or be less likely to die, and they can provide the necessary sustain to survive laning phase.
So the next time you wonder whether a champion will make a viable support, consider these three attributes and whether your champion has enough of them to make them viable as a support.