1/6 increases the oracle level for a selected revelation, ie Form of the Dragon works as a 14th level ability by 12th level, or would he have to wait until he has the revelation in order to add the favored class bonus. The later makes it a terrible option for anything that comes 9th level and beyond.
I believe you can't. Can't find the ruling for it, but I think it's been rules you actually have to possess the class feature before you can FCB it. Similar to how you can't modify your car if you haven't bought it yet.
There was an FAQ about it somewhere, you can't.
It's the same FAQ that establishes human barbarians can't take the bonus to Superstitious until they choose that rage power.
You would have to wait.
If an alternate favored class option modifies a class feature or ability, it can't be taken before the character has that class feature or ability. For example, if a class gains a class feature at 6th level, a character couldn't take a racial favored class option that applies to that class feature until 6th level, even if the benefit from that option wouldn't be high enough to add a bonus until a later level.
That kind of FCB is really what ruined it for everyone else, because it used to be a 1/2 increase instead of 1/6. With some FCBs, it would have been perfectly sensible to allow it to be taken starting at level 1 even if you don't have the ability yet. But because of the abuses, that new rule had to be added.
I see, thanks.