var texture1 : Texture2D;
var texture2 : Texture2D;
var alreadyUpdated = false;

function Update() {
    if (!alreadyUpdated && Input.GetKey(KeyCode.X)) {
        alreadyUpdated = true;
        RenderSometing();
    }
}

function RenderSometing() {
    yield WaitForSeconds(9);
    renderer.material.mainTexture = texture1;

    yield WaitForSeconds(9);
    renderer.material.mainTexture = texture2;
}