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Yes, they are. We still have a couple of the 9.6v's and use them when we demo or rent Leaf Aptus backs on an H2, because the Leaf won't benefit from using the 7.2v Grip, which in addition to the camera, powers the "D" part of the H2D and H3D.
So, it will power an H1 or an H2, but if you're using an H2D or an H3D, it won't power the "D". If you're using film or a 3rd party digital back, it's fine.