How to get my 9 month old kitten to stop biting?

My kitten is 9 months old, his name is Hugo. We've had him for aboout 5-6 monthish. He is loverly and very playful, sometimes he will be really sweet and enjoy fuss but sometimes he will just randomly start biting and scratching your hand while you stroke him, its really painful. How can i teach him not to do this? and make him remember it too? i have tried shouting at him.