For 9 yrs old I think you have a lot of talent.. Keep at it.. Listen to what others say here.. and elsewhere.. you will go far! For now, work on shading and getting rid of outlines That's for coloring books.. your work is Real Art!!
Great job! Are you totally into Manga, or is that what you first learned to draw? If you want to do Manga, you got it! If you want to do more realistic drawing my advice is start learning now. I have heard people talk about getting "trapped" in the Manga style and having difficulty doing anything else.
The most important thing; if your art isn't fun, you're doing it wrong!