Edit in JSFiddle

window.addEventListener("load", init);

     function init() {
      var stage = new createjs.Stage("myCanvas");
			//
      var ball = new createjs.Shape();
      ball.graphics.beginFill('#aaaaaa').drawCircle(0, 0, 30);
      stage.addChild(ball);
      var angle = 0;
      var centerY = 100; // 中心座標
      var range = 50; // 変化幅
      var xSpeed = 1;
      var ySpeed = 0.05;
      // 時間経過
      createjs.Ticker.addEventListener("tick", handleTick);
      function handleTick() {
        ball.x += xSpeed;
        ball.y = centerY + Math.sin(angle) * range;
        angle += ySpeed;
        // 画面端
        if (ball.x > stage.canvas.width) {
          ball.x = 0;
        }
        stage.update();
      }
      createjs.Ticker.timingMode = createjs.Ticker.RAF;
    }