If you are only quilting eight inches apart on your diagonal, then do the opposite direction too minimum. First for strength of your quilting. I always assume baby quilts will get washed more often. Then for looks. It may appear slightly "unfinished" without the opposite direction of quilting. I would also suggest quilting more heavily again because it will be used with differently than even a throw quilt. It is for a baby. Keep your diagonals, crosshatch style, but move the lines closer, perhaps 2 inches. After washing once and the natural puckering happens those lines will all blend in and hold the piecing firmly in place for lots of use and loving.
I have taken to doing channeling on baby quilts about an inch apart. Easy and mindless quilting that does not hide the pattern or piecing. My other go to option is a vertical wavy free motion style line that moves from one inch apart to about two and a half inches apart. The wavy lines do not echo each other but just flow up and down the quilt top.
But after making these comments and suggestions, do what you feel is appropriate for this quilt, your work and what you feel looks the best. My take largest suggestion is that 8 inches may be good for the design, but perhaps not so good for a quilt that will be laundered more often and hopefully used every day snuggling a special someone.
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