You can't really expect to win if he's really good. Even though you're on the almighty Renekton Kennen is a pretty strong and consistent ranged champion and in Riot's almighty wisdom they let ranged champions abuse Doran's Shield and Ninja Tabis if ones gonna be that scummy too (like Teemo can easily afford Tabis because his dot damage is soo high)
But you should be able to endure. Maintain relevant cs and be gankable at least on average. Especially in sub diamond find openings hopefully. You must have you own teleport if you're not confident in the ignite cheese and you should start doran's shield because it's really op. Cloth 5 (now 4) died a long long time ago. 50g per pot is a waste of gold. You should ideally get refill pot every single game.
But it really sucks melee always have to start the game out being assaulted by ranged ad, even the "strong" melee lane champs. If they slow push and zone from level 1 slow enough you'll be forced to wait to cs a big wave under your tower and if your jungle doesn't show top to at least scare them away a bit you'll probably be put at an hp deficit TP loss situation. But what if Kennen's jungle was around top too and so your jungle can't fend em off without getting 2v1'd while you have to cs under tower or your jungle has to leach your lane exp putting you behind....
Hexdrinker and Ninja Tabi in particular are strong items but at both you're definitely suffering a damage loss. Part of the Kennen problem is his damage is mixed. When AD Kennen was highly contested in the LCS even though he fell off many games part of his strength was his flexible itemization to go wits end for lots of magic dmg or AD items. He dictates your build path. I don't see AD Kennen anymore though however for AP Kennen ADC runes are actually better for early game. Either full ADC or swap 15 ap for attack speed because AP hardly does jack especially early.
On the bright side Renekton is good because he abuses Fervor super hard.
Ninja Tabi in particular is really good because the mitigation is unparalleled at the 1000g point and mobility is important for everything to fighting to returning to lane to roaming to dodging skillshots and running into cs range and out of range. Merc's aren't bad either however. I consider shoes even more important than most people.
But yeah with the current game design melee typically only beat ranged by outplaying with more difficult playstyles or tanking up so hard. And tanks are super strong true but ultimately they are pawns of the ranged dps champs.
You could try Pantheon or Wukong'ing them (he's like a cheese version of Irelia) or join them or become a better player than them...
I'd recommend buying Doran's shield though. Level 1 pushing in is typically not at all recommended . You CAN cheese them with a gap close + burst levels but it can also put you in bad situations where you pushed forcing you to contend dying cs opening yourself up to more poke and gank risk. NEVER push level 1 as melee vs. ranged if yours isn't equipped to either cheese or have somehow ridiculous level 1 push power. Even up to plat I actually show up for lane late intentionally and see if they start pushing and when I see they do that versus TEEMO I know it's gonna be an easy game. I learn a lot about a player 5-30 secs in lane based on their champ and item aggression and lane manipulation.
Unfortunately league isn't much a game of skill as it is about bitch moves, knowledge and yeah teamwork.
Once you have a few levels you should be able to contest as Renekton though and not play so back. But everytime you want a say you put yourself in more risk of ganks than Kennen does and that sucks.
Another suggestion I might have is Olaf. He has strong ranged waveclear, can potentially pwn scrubs and basically defies the laws of melee with his ult. Righteous Glory might be kewl on him. He has super dps potential too.
