I'd be tempted to go with this for Ninetales:
Ninetales@Leftovers
EV: 252 HP, 129 Def, 129 Sp Def
Nature: + Sp Att, - Att
Fire Spin
Toxic
Confuse Ray
Flamethrower
One of those rare occasions when you use two move of the same type. Fire Spin to trap, while Toxic and Confuse Ray does damage and they can't escape. Ninetales is fairly fast for an annoyer, so you may also consider more of a sweeping set.
Ninetales@Lum Berry
EV: 252 Speed, 252 Sp Att, 6 Sp Def
Nature: + Sp Att, - Att
Flamethrower
HP Grass
Quick Attack
Will-O-Wisp