Technically ireila should win the lane. As soon as she gets 4 she should just jump to last hit a ranged then right onto you and insta kill you.
And ireila "does" counter kennen because her slow/stun makes lightning rush useless.
I'd have to disagree.
Any decent Kennen would use his ranged pokey bursty good stuff to zone irelia out.
Imo, it would probably just be a farm fest until Irelia got some tanky items, then she would probably shit on him unless he got some sort of sustain ie hextech