Put two wide angle lens (aka a standard GoPro) on the thirds of the length of the crossbar.
Suddenly you have two cameras in the net that can see down, are out of the direct line of the goaltender and will grab his visibility from both sides of the net.
It seems like a really simple fix. The only thing they have to worry about will be how to integrate them into the net so that the bar stays flush and if they're hit they won't shatter.
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