I have go hold of a KAM BDX900 USB turntable and was wondering if I can play this through my MacBook or do I need an amp? Any help appreciated.

What do you mean by “play it through your Macbook”? Do you want to record your vinyl in Audacity?
Since it is a USB turntable you should be able to just connect it to a USB port and then record your vinyl with Audacity. If you have the turntable and Macbook why not just connect them and see if it works?
– Bill