Roll A Ball game camera controller help!

Hello i watched the tutorial how to make roll a ball camera that is like i want but not rly. I want it to be able to zoom in and zoom out with scroll wheel and rotate camera around the ball with a and d a is left d is right. How can i do that? please i need help.

Here is the code:

using UnityEngine;
using System.Collections;

public class CameraController : MonoBehaviour {

	public GameObject player;

	public float moveSpeed = 10f;

	private Vector3 offset;
	
	void Start ()
	{
		offset = transform.position - player.transform.position;
	}

	void LateUpdate ()
	{
		transform.position = player.transform.position + offset;

		//if(Input.GetAxis ("Mouse ScrollWheel") > 0f ){
		//	transform.Translate (Vector3.forward * moveSpeed * Time.deltaTime);
		//}
	}
}

I will still try to fix this problem my self but i cant seem to find a way to do this. Thanks.

I fixed it but it was hard. I made a custom ball anchor that does not change.

BallAnchor:

using UnityEngine;
using System.Collections;

public class BallAnchor : MonoBehaviour {

	public GameObject ball1;
	private Vector3 offset;

	// Use this for initialization
	void Start () {
	
		offset = transform.position - ball1.transform.position;

	}
	
	// Update is called once per frame
	void LateUpdate () {
	
		transform.position = ball1.transform.position + offset;

	}
}

And then this is the camera component:

using UnityEngine;
using System.Collections;

public class CameraController : MonoBehaviour {

	public GameObject ball1 = null;

	//public float moveSpeed = 10f;

	//private Vector3 offset;
	
	void Start ()
	{

	}

	void Update ()
	{
		if (ball1 != null) {

			transform.LookAt (ball1.transform);

			//if (Input.GetAxis ("Mouse ScrollWheel") > 0f) {
			//	transform.RotateAround (ball1.transform.position, new Vector3(0, 1, 0), Time.deltaTime * 150);
			//}
		}
	}
}

Camera GameObject is set to the custom ball anchor and the camera is custom ball anchor child.