If the blocks are 9" and the batting requirements are 8", then you do need more quilting in the areas around the ovals/trucks. That 8" requirement means in all directions. Even just a a straight line echoing the edge of the block will help to secure that batting. I try to think about how the quilt will be used....a quilt that won't get washed much doesn't require as much quilting as one that could get washed every week....the more batting is washed, the more it might shred, bunch or shift (think old comforters and how the batting ends up in one corner).