Cat form at level 8 is great, except that casting thorns breaks form, and returning to cat form leaves you with no energy for a long time. I guess thorns is designed for the caster specs. I know that on my Resto druid I cast thorns on the tank as much as possible. Of course moonfire also breaks form as expected, leaving no way to range pull except to switch to Troll Form, pull, switch back to Cat Form, which would be okay, except for the energy problem. Getting 3 points into Furor will solve the problem, but assuming you take Feral Swiftness first, it's going to be level 15 before you have a couple of points in that talent. Faerie Fire is a level 24 spell unfortunately.
At first I used a rotation of Rake, Claw(Mutilate at level 10), Bite-- the idea was to put up Rake first, so you could get max ticks out of it before the mob died. During these levels nothing lives that long. Claw, Claw, Bite pretty much killed anything. Sometimes, I would just save the energy, just Claw/Mutilate twice and skip Bite.
The troll cat form itself is very trollish and Blizzard did a good job of making them very unique compared to Taurens and Night Elves. I've always preferred the sleek dark Panther look of the Night Elves, very Jazzy, just like the Cat Form dance. On the other hand, the trolls are punk rockers who think punk rockers are all posers. I was admiring my cool unique cat form appearance at level 8, when a twin druid ran up the trainer.
I hit level 15, trained up the Bear spells, and next time I have a couple of hours, I'll queue up as a tank. It'll be fun comparing low level instances between tanking and healing.