I think I would go with a cross hatch. It’s a little time consuming on something with so many 9 patches to get through, but it will look nice. Plus, it will be tight enough to handle the wear and tear of usage. Be extra careful with the backing if you go this route. A walking foot works best. If using a regular foot, you should start at the center and work your way out to the four corners so the backing doesn’t bunge up (even if you pinned it meticulously). After a few rows, stretching the points in opposite directions should avoid overlap. Perhaps you know all this…for a long time I didn’t and I spent a lot of time pulling thread and easing backing. So I’m just throwing it out there if you can use it.
Eric The Quilter 
I think I would go with a cross hatch. It’s a little time consuming on something with so many 9 patches to get through, but it will look nice. Plus, it will be tight enough to handle the wear and tear of usage. Be extra careful with the backing if you go this route. A walking foot works best. If using a regular foot, you should start at the center and work your way out to the four corners so the backing doesn’t bunge up (even if you pinned it meticulously). After a few rows, stretching the points in opposite directions should avoid overlap. Perhaps you know all this…for a long time I didn’t and I spent a lot of time pulling thread and easing backing. So I’m just throwing it out there if you can use it.