Watching a Summer Koshien Baseball Game

Hello, I'll be in Japan in August and thought I'd try to catch a Summer Koshien game. It looks like the prices are the same regardless of day, so I was thinking I might as well watch the championships on the last day, August 17, 2024? Is that right?

Also, I'll be travelling with a 6 year old, 4 year old, and 1 year old. Is the environment likely to be too loud for the 1 year old? I'm thinking that even the older kids might get bored, are we allowed to go in and out of the stadium?

Thanks!