In PFS can a Warpriest or Tempered Champion Plaldin that has a bite attack, likely due to race, use their bite as their sacred weapon? If so, how dose that affect things like Divine Bond?
Yes, a Warpriest gets to bite as a sacred weapon. It's the favored weapon, and that's what they get by default. As for the paladin, same answer. Are you questioning whether a bite is considered a weapon? Natural weapons are still weapons, the distinction comes when something specifies manufactured weapons.
It makes for a very fun Tenth Warpriest of Apsu with Weapon Focus (claw)!