It depends on the specific publisher and the official stance. Sometimes it might be canon, but other times it could be more of a side story or alternate take.
In fanfiction, young Joseph Joestar is often depicted as highly energetic. He's always ready to jump into action, whether it's facing off against an enemy or trying to impress a girl. His brashness is also a common trait. He may rush into things without fully thinking them through, but his quick thinking usually gets him out of trouble.
There are fan fictions that explore Joseph's early years in more depth. Maybe a story that focuses on his training with Caesar and how that relationship developed further. This could show his growth as a character from a young, brash fighter to a more strategic one.
Well, it's hard to say for sure. It could be inspired by real life, or it could be completely fictional. You'd have to look at the details and the context to determine if there's any truth to it.
Well, 'Joseph's Second Chance' is a notable one. It has a well-crafted story where the de-aged Joseph faces new challenges and grows in interesting ways. The author does a great job of maintaining the essence of the character while exploring this new age dynamic.