Since the answers came from Sonic Team themself, then I guess whatever Sonic says would be the new canon.
On the spin dash question, I always imagine Sonic has vertical 360° vision given he's spinning and that his brain picks up what he sees and maps it in his mind in a vertical panorama sort of way.
As for how he does the homing attack, my theory is that when he became Hyper Sonic is Sonic 3 & Knuckles, he instinctively knew how to perform the
Hyper Flash granted to him by the transformation.
While afterwards (Sonic 4 or Adventure) he was no longer Hyper Sonic he still remembered the method of the Hyper Flash which is he recreates as the jump dash.
As for the Homing Attack, as I said I believe he has vertical 360° panoramic vision so it could be possible he uses it to lock-on to his target and jump dash towards them.
But that's just a theory, a Sonic theory.