Like crabs said and after looking at the code, Penny's Day 8 scene should only be offered if you do any of those 4 scenes with her regardless if you're on any other routes. I might have overlooked something somewhere, though.
I swear, I've been holding down control key for an hour, restarting the game over and over again, trying every possible combination to not trigger that scene, I've avoided every interaction with her possible. Naturally because I only wanted Zoey, I've avoided every other route as well. That scene triggered for me regardless, and I only stopped getting it when I started getting on different routes. The only non-sexual route I found was Malik, because you can decline sex with her at her house, as opposed to other routes, where blowjobs just happen and you can't say no.
Also, I've been wanting to add a rejection choice for that scene for a while but never got around to it. So next update, I'll be adding one for that and any other sex scenes that don't have one (mostly in week 1).
Bless. I am one of the people that thinks all sexual content should always be optional, not just because sometimes I want to roleplay an MC that doesn't take sex casually, but also because I don't find every girl hot and I want to see the scenes only with the ones that I find hot. If there would be a choice to not kiss / get blowjobs / see people naked ( like the Malik option where you HAVE to choose between blowjob and seeing her naked ) / sex etc. and a choice to close started routes, it would be ideal, because otherwise I love the game.
Other than that, I had one more question. I got the game on Steam awhile ago, and the latest update added animations and stuff, but the version on Steam seems to be lagging behind in content currently. I got to Zoe sex with this version here on F95, but on steam the game ends after the battle.