Cheiromancer
Adventurer
Oops. I misread the spell. I thought it was strength, dexterity or constitution.
Still, I don't see why 8th level wouldn't be sufficient. No spells, plus lots of dropped spell slots for what is a very short duration animal buff spell... Most characters who would benefit from a +9 to those ability scores would already have substantial enhancement bonuses already. If a character already has +4 or +6 to those ability scores, they don't get much benefit from the spell unless the spell preparation dropped is of very high level. And every 8th level preparation dropped has a pretty high marginal cost.
And having it be the same level as the other spells would make things seem more tidy.
Still, I don't see why 8th level wouldn't be sufficient. No spells, plus lots of dropped spell slots for what is a very short duration animal buff spell... Most characters who would benefit from a +9 to those ability scores would already have substantial enhancement bonuses already. If a character already has +4 or +6 to those ability scores, they don't get much benefit from the spell unless the spell preparation dropped is of very high level. And every 8th level preparation dropped has a pretty high marginal cost.
And having it be the same level as the other spells would make things seem more tidy.