A smaller size of the same listed construction
This entry can be compared with a black size 11 listing using the same photograph and side-zip description. The size change does not establish a different protective design. This page is useful when locating the size 9 offer, while the model identification still needs checking on the selected item.
Assess the opening and ankle area
Try the zipper through its full travel while the boot is on. An opening that catches your sock or presses beside the ankle can make repeated changes inconvenient. Select another size only if it resolves the actual fit issue, rather than expecting the zipper to create extra width.