Is cat aggression normal?

Staying with my bf and his roomate and I usually bring my 9mo old kitten over. Her claws are trimmed and she loves to play with the roomate’s 6yr old male tabby. They love snuggling and playing together, and he’s usually pretty nice. I dropped my water bottle in the kitchen and my kitten just stared at me, but the male cat started hissing and tried to bite me. This happened again a few days ago, and he managed to draw blood and leave a deep scar (this was after I told my kitten no to scratching the couch). The cats never get aggressive at each other, and my kitten never hurts the cat, but he’s always attacking me??? I hate scars sm but idk if this is just normal cat behavior bc he’s old and grumpy.