"Yarutte" is actually not THAT formal -- it's sort of typical boyspeak, for Sora's level. (Hence why you can hear shounen heroes yelling things like "MISETEYARUZE!!!!" at their Eternal Rivals before exploding together in a ball of burning fire.)

I'm at work, so the Japanese characters aren't displaying properly, but literally I would translate "tokubetsu ni nosete yarutte" as "we'll give you a [free] ride" -- i.e., it's REALLY COOL and you can ride it FOR FREE (special) because YOU ARE COOL TOO :D :D :D -- only Riku's not getting that.