Just Soft Reset your game.
As soon as you defeat the Elite 4 and Champion and get entered in the Hall of Fame the game saves automatically providing you don't turn it off before it has chance to save. So if you Soft Reset after the game has been saved you'll end up in the player's house.
You can Soft Reset by pressing and holding L + R + Start or Select. Soft Resetting is essentially the same as turning your 3DS off and then back on again.
You can also fast forward the credits by pressing the A or B button.
Hope I helped :)