Python 2, 79 69 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)*w%(h*w)for q in range(9)if q-4]

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0-indexed solution.

Python 2, 79 69 66 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)%h*w for q in range(9)if q-4]

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3 bytes gifted by Neil noting that (x*w)%(h*w)==((x)%h)*w==(x)%h*w.

0-indexed solution.

Python 2, 79 69 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)*w%(h*w)for q in range(9)if q-4]

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Python 2, 79 69 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)*w%(h*w)for q in range(9)if q-4]

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0-indexed solution.

Python 2, 79 70 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)*w%(h*w)for q in range(9)if q!=4]

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Python 2, 79 69 bytes

lambda h,w,i:[(i+q%3-1)%w+(i/w+q/3-1)*w%(h*w)for q in range(9)if q-4]

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