I'm a beginner and recently abandoned 1.e4 to play the Kings indian attack starting with 1.Nf3. Ive been winning more when I play amateurs at school, however when I play people rated 1500 and up on the internet I am ripped apart and was wondering if this technique is sound for highly rated players?

White wins 41.6%
Black wins 29.3%
Draws 29.1%

Got those stats from chessgames.com so I'm guessing yes but if black plays perfectly against it and white plays it perfectly who is better off?

Also any success stories or anyone who uses it constantly for a specific reason?

One last question what do you think of the Kings Indian attack for both beginner and grandmaster level?

I wrote an article in the 1970's for CCLA on the King's Indian Attack.
There were several books/monographs available on the subject.
What Black has to be careful about is not play a reversed Opening.
When Black plays a reversed Indian Defense, Black fall one tempo or more behind.
White: See the comments on Exeter Chess Club: Introduction to the King's Indian Attack
Bobby Fischer played the system in more than several games.
A DVD on the system is available at http://www.wholesalechess.com/chess/King's+Indian+Attack.
A book is available:
Amazon.com: Starting Out: King's Indian Attack (Starting Out - Everyman Chess): Books: John Emms

One thing you do need to know: White’s correct strategy will depend on the type setup that Black uses. King’s Indian, Sicilian, French, etc. formation by Black will all require a different strategy by White. There is no one size fits all opening so like any other opening, you will still have to learn different strategies.

Once again, when playing the KIA lure Black into a reversed Grunfeld, Kings Indian. The post above indicated the Sicilian, and the French. Back in the 60's
more than a few GMs played against the King Pawn Defenses the KIA.
When you run into a problem, realize it may be that you are copying moves without knowing why the moves were made. So when going over Fischer, or Bronstein games with the KIA ask yourself why the move was made.
Sort of like Chernov's book, Logical Chess. Always think in those terms.

Interesting. How would you recommend I should have played the opening in the following game?

Chess PGN Game Replayer

Game resembles a Reti Opening rather than a King's Indian Attack.
These are two available games in the data base:
[Event "Troll Masters"]
[Site "Gausdal"]
[Date "1990.01.??"]
[Round "7"]
[White "Carlier,Bruno"]
[Black "Gausel,Einar"]
[Result "0-1"]
[Eco "A07"]
1.Nf3 d5 2.g3 Nf6 3.Bg2 c6 4.0-0 Bg4 5.d3 Nbd7 6.Qe1 e5 7.e4 dxe4 8.dxe4 Qc7
9.Nbd2 Bc5 10.h3 Bh5 11.Nh4 Bg6 12.Nb3 Bb6 13.a4 a5 14.Bd2 Nc5 15.Nxc5 Bxc5 16.Bc3 Nd7
17.Kh1 f6 18.Nxg6 hxg6 19.Rd1 Bb6 20.Qe2 Nc5 21.b3 Qc8 22.Kh2 Ne6 23.f4 exf4 24.gxf4 Bc7
25.e5 f5 26.Qe3 0-0 27.Rd3 Rd8 28.Qg3 Rxd3 29.cxd3 Qe8 30.d4 Rd8 31.Rd1 Nc5 32.d5 cxd5
33.Bxd5+ Rxd5 34.Rxd5 Qc6 35.Qf3 Ne4 36.Rd3 Bb6 37.Bd4 Qc2+ 38.Kg1 Qc1+ 39.Qd1 Bxd4+ 40.Rxd4 Qe3+
0-1

[Event "EU-ch63 sf03 corr"]
[Site "ICCF corr"]
[Date "1999.01.04"]
[Round "0"]
[White "Burgarth,Ulrich"]
[Black "Kramer,Svend Erik"]
[Result "1-0"]
[Eco "A07"]
1.Nf3 d5 2.g3 Nf6 3.Bg2 c6 4.0-0 Bg4 5.d3 Nbd7 6.Nbd2 e5 7.e4 dxe4 8.dxe4 Qc7
9.h3 Bh5 10.Qe1 Bc5 11.Nh4 Bg6 12.Nb3 Bb6 13.a4 a5 14.Be3 0-0 15.Nxg6 hxg6 16.Bxb6 Qxb6
17.Qc3 Rfd8 18.Rfd1 Kf8 19.Rd3 Ke7 20.Nd2 Qb4 21.Nc4 Qxc3 22.Rxc3 g5 23.f3 Nh5 24.Kf2 g6
25.Rd1 Nc5 26.Rxd8 Rxd8 27.b3 Ne6 28.Bf1 f6 29.Rd3 Ra8 30.Nb6 Rd8 31.Rxd8 Nxd8 32.Nc4 Ng7
33.Nxa5 c5 34.c3 Nge6 35.Bd3 Nc7 36.b4 b6 37.Nc4 b5 38.Nb6 bxa4 39.Nxa4 cxb4 40.cxb4 Kd6
41.Nc3 Nc6 42.b5 Nb4 43.Bc4 Kc5 44.Be2 Ne8 45.Na4+ Kd4 46.Nb6 Kc5 47.Nc8 f5 48.b6 Kc6
49.Bc4 Kb7 50.Bf7 Kxc8 51.Bxe8 f4 52.Kf1 Nc2 53.h4 Nd4 54.Kg2 fxg3 55.hxg5 Ne2 56.Bxg6 Nf4+
57.Kxg3 Nxg6 58.Kg4 1-0