Btw, I beat Ruby's time attack challenge (1'13") but he has failed to open the SEGA Forums thread for me to post the photo. Probably cuz he's scared.
A note about the homing attack: You only get one chance to hit something with it in the air. If you fail to make contact with anything you can't use it until reaching the ground and jumping again. This is nice, as it cuts down greatly on spamming the attack. However, if you use it and hit something, it resets and can be used again (to chain). So thankfully, it cannot be spammed.
Example: I tried running off an enemy-free ledge and used the homing attack to mid-air dash but then while coming down I thought I'd sneakily boost again towards an item box, but was unable to perform a second HA as my first did not make contact with an enemy or item.