[[:Category:Name]] (with a leading colon) lets you mention and link to a category without categorizing the page.
I just wondered why my message wall was sudddenly categorized. :D
About your question: They are different categories, the first contains seasons, the latter contains different race modes. At least it should; the categorization in this area is not quite consistent at the moment.
I've changed the category of the season 9 page you have worked on so it is in the right category now.