That's why he said don't buy her if you play ranked.
I tried Kennen but I could never figure out how to work the abilities and energy stuff (maybe I was supposed to have an energy-specific rune page or something). I guess I would need to farm a lot so I'm tanky enough to not immediately die if I ult, until I get hourglass.
Normal draft isn't ranked. :I
Kennen is ultimate harass machine with his Q and normal attack buff passive thing. You don't really need energy-specific runes to play him.