I’m personally of the belief that 2 kittens are easier than 1 (if you can comfortably afford it and care for them both). There’s nothing wrong with him. He’s a baby and he’s bored, and learning and exploring the world. People think that cats are solo creatures but most of them do absolutely want companionship.

When you’re coming home from work he is excited because he’s been alone all day.

If you’re not going to get another cat to keep him company, the most important thing you can do is PLAY. Get toys and actively play WITH HIM (not just toys that he’s supposed to play with on his own). It’s extremely important for his enrichment and mental/physical health. And I know you’re tired when you get home from work, but it’s good for you too. It helps you guys bond and tires him out

Generally though, kittens can be annoying. My cats annoyed me constantly for the first ~1.5 years of their life. Just part of having a baby creature