Battle Moveset

A Good Moveset for Ninetales would have to be this:

Attacks:

Flamethrower
Confuse Ray
Fire Spin
Toxic

Items Attached:

Leftovers

Preferred Nature:

Calm

Strategy Using Ninetales

Before I begin explaining this moveset, there's something I would just like to add: Will-o-wisp + Confuse ray DO NOT work together, Will-o-wisp reduces attack and confuse ray will become almost useless, dealing less damage if your opponent hits itself in confusion.
Anyways, now that's been explained, onto this moveset. Ninetales is an excellent annoyer, with great speed and great special defense, it can take its fair share of hits, especially special type moves.
Ninetales also has a nice, unique and wide movepool to use, allowing quite a few variations on this annoyer moveset. Each move works in Ninetales favour, Confuse ray to up that chance of the opponent hitting itself, and giving you an extra turn to attack.
Toxic works well with Fire Spin, since Fire Spin prevents your opponent switching pokemon, Toxic will gradually result in dealing more damage, with the added damage done by Fire spin too on a turn to turn basis.
Flamethrower is the last move you're most likely have left to use if Confuse Ray, Toxic and Fire spin are still in effect. Flamethrower gains STAB and can sweep away those Steel types that are immune to Toxic. Flamethrower and Fire Spin gain a boost in strength from Ninetales Flash fire ability.
As for the EV's, 129 in HP should be useful, just to give Leftovers a little extra boost in worthiness. The rest EV's should be used to pump up defense, the more hits it can take, the more damage it can deal out. Although Leftovers could be replaced with items such as the pinch berries, such as Ganlon/apicot berries, for an extra boost in defense

EV Corner:

Max out the EVs in Defense for Ninetales with any remaining in HP & Special Defense

Strategy Against Ninetales

Ninetales' Defenses are above average but it's Physical is lower soa Physical Volley or a Water, Rock or Ground Volley should work wonders

Contest Moveset

A good Contest Moveset for Ninetales would have to be this for the Smart Contest best with Calm, Gentle, Careful, Sassy Nature:

Attacks:

Body Slam
Imprison
Confuse Ray
Flamethrower

Items Attached:

Green Scarf

Strategy Using Ninetales

If you do the attacks in this following order you should have very few problems; 1st - Body slam, 2nd - Imprison, 3rd - Confuse Ray, 4th - Body slam, 5th - Flamethrower

Locations in Games

Ruby/Sapphire/Emerald Evolve Vulpix Colosseum Trade from R/S/E/FR/LG Fire Red/Leaf Green Evolve Vulpix

Animé Appearences

Ninetales has had a few Animé Appearences. First Blaine used one in his battle against Ash's Squirtle, After that a trainer that went to New Island had one which was thus cloned. After that, a friend of Suzie's had one in a Breeding Contest. After that a very old one thought Brock was it's trainer. The Rest are Cameos Episode 040: The Battling Eevee Bros! Episode 058: Riddle Me This! Movie 1: Mewtwo Strikes Back! Movie 2: The Power of One Episode 171: Beauty & The Breeder! Episode 234: Just Waiting On A Friend! Special 2: Mewtwo Returns!