What can be used to whiten your teeth so amazingly. It looks like all the movie stars teeth? I'm very curious.

Many options. There are many options, depending mostly on your budget. Movie stars usually have "caps" (thin white covers) applied to their teeth, or "bonding", in which a white resin is applied and hardened with a special light. Various bleaching compounds are available from your dentist, and most work if you use them diligently. Whitening toothpastes, however, (according to my dentist) are ineffective.
Depends. Movie stars with ideal, perfectly shaped, and perfectly positioned white teeth typically have porcelain laminate veneers or all ceramic crowns on their teeth. Those whose teeth are in less than perfect shape, position or color may have had in-office or home teeth whitening treatments.
Whitening. Whitening, using a bleach designed for teeth, is one method of getting whiter teeth. Other ways are to place veneers of porcelain on the front of teeth or placing crowns that completely cover teeth. However, most young people have teeth that are very white naturally. Using veneers or crowns strictly to have a whiter smile is unwise at your age. Professional bleaching is probably your best bet.