Prevalent is that you've already prevailed, and prevailing is that you're in the act of prevailing.

Both. It depends if you're talking in present tense, like you're sitting there, watching Jim playing, or if you're referring to something that happen a while ago and you're not there. In the case of present tense, 'scored' would be right. Past tense would be 'had scored.' This sentence leans a bit to the past tense, so it would sound best as 'had scored,' although I wouldn't personally do that, because it seems proper. Scored works too, but I believe the grammatically correct one for past tense would be 'had scored.'

My hobbies

My favorite hobb<font style="background-color: yellow;">y</font> is read<font style="background-color: yellow;">ing</font> books, I like books about science fiction, drama or romance, but now I don't like youth books because I have read many of those books and I think <font style="background-color: yellow;">they</font> have very similar stories.
This year I have read many horror books <font style="background-color: yellow;">written by</font> <font style="background-color: yellow;">S</font>tephen <font style="background-color: yellow;">K</font>ing <font style="background-color: yellow;">such</font> as IT or <font style="background-color: yellow;">C</font>arrie.  I like <font style="background-color: yellow;">his books</font> more than his movies because I know what the characters think.
My other hobb<font style="background-color: yellow;">y</font> is <font style="background-color: yellow;">to</font> exercise. I exercise everyday when I lift weights. <font style="background-color: yellow;">S</font>ometimes I run in the park near my house<font style="background-color: yellow;">,</font> but only when I have free time.