I like all the ideas so far.
Mine was add borders to the one large to make quilt as big as you like. Then a mobile with the smalls. But 9" is big for mobile, so maybe 2 soft stuffed pillows.

You could make a pillow case. I made pilow cases for grandkids out of fabric added some fabric for a few that were short. They loved them. Then made them for my kids adult fabric hunting, beach, van go stary night, soccer and baseball. All are in use happy to say was not sure they would be.

I would make a smaller quilt with the 9" blocks. With winter coming it would be nice for a blanket for the car seat or covering baby up going in and out of the cold weather.

I would make colorful pinwheels to make the main panel at least 42 square as a playmat for tummy time and put the smaller panels on the back so the quilt is two sided. Or you could make a cute matching tote bag out of the other squares.

I completely agree with this... most of my "baby" quilts are at least 45x60 - or even larger. I want the child to be able to use the quilt until it completely disintegrates... and a little 24x24 (or so) will not get "used up" the way I prefer.

The cornerstones suggestion was good - add a nice border (stripes maybe?) with the cornerstones, and you have a nice big quilt for baby/child to drag around forever.