Hard for me to understand the recommendations for a smaller FOV and limited eye relief maginified optic for a 9mm semi auto sub gun.... and for $1000....
I'm thinking it's more about what THEY have vs what would actually make sense....
A (quality) micro red dot sight would probably make the most sense. Small, unlimited eye relief, better field of view, plenty accurate out as far as your will be able to accurately get hits with 9mm...
If 100yd is a factor, then it's likely out to 200yd or more is also very likely, in which case you'll want a real rifle. Which are damn near as compact as a subgun these days, which is why the sub gun is kinda dying out.
ETA: The version of the Trijicon optic mentioned might not be as magnifying as I assumed, but at 1.5x I don't see why it needs to cost $800+ or be as large and heavy as it is for what it does.