I can't speak specifically for going from weekly to biweekly, but I did try going the opposite direction. I do my shots biweekly and tried to go weekly, and it completely screwed with my mood. I've never had a single mood issue or any issue for that matter, on what is considered the standard "full dose".
At over 9 month on T, I imagine your changes are slowing down anyways, switching to biweekly won't cause them to go slower. I don't have terrible acne, I get some pimples here and there on my chin, and my back, but then again I had basically perfect skin before testosterone and rarely got so much as a blackhead before. (I miss that lol)
I personally prefer biweekly because it's just that less often that you have to mess with doing your shot.. It was exciting at first but it loses its thrill after awhile haha.