This is my first time answering a question, so i hope that will be all right :)
First of all, the position appearing on the board is also reached via this move order: 1. Nf3 d5 2. g3 c5 3. Bg2 nc6 4. O-O e5 5. d3 Nf6 6. Nbd2 Be7 7. e4 dxe4 8.dxe4 and it's a tempo up for black, and the extra move might be important. And secondly we might reach this position with colors reversed: 1. d4 Nf6 2.c4 g6 3. Nc3 Bg7 4.e4 d6 5. Nf3 O-O 6. Be2 Nbd7 7. O-O e5 8. dxe5 dxe5 etc. And it's very important to notice that the examination of similar positions provides complete understanding of ideas.
Bypassing the move order and transposition issues, I would like to mention the related article named "The King's Indian Attack (from White's Viewpoint)" (page 142) on the excellent book Opening Preparation by Dvoretsky (1996), Dvoretsky came to the conclusion that this exchange (...dxe4 and ...e5 by Black) is dubious. The reasoning behind Dvoretsky's assessment is:
"Not a good exchange. White now has a clear plan for playing on the weaknesses c4, d5 and f5."
In the game (which cannot be found in databases) Dvoretsky - Rogozhnikov, Moscow 1965 White executes his plan by playing, c3, Qc2, Nf1 and exchanging the defender of d5 square by Bg5-Bxf6 and after Ne3, Bf1 and Bc4, and exchanging the best defender, the light-squared bishop on e6. It should be noted that Dvoretsky's opponent defended weakly and lost after a beautiful positional squeeze. But it's not clear how White will react after the correct a timely ...h6 and countering the White's plan by trying to push ...c4 by ...b5 or ...Na5
Maybe the answer is the mixture of the whole ideas given, let's say, Nc4(Nf1)-Ne3 and Nf5 and after an exchange on f5 to take with exf5 and play with the strong bishop g2 and full control on the light squares. There are many typical master games with both colors. You might want to search the other transpositional options in order to achieve complete understanding of the ideas, because there are hundreds of master games beginning from those positions with both colors. I hope I might be able to help you.