That is not implied though. You're focusing on Sekai taking hold of her to kiss Akira, in that sense it is implied yes. But from the time Akira meets Kaori way in the beginning (in chapter 1) and has a date with her, she starts to mention multiple times that she is physically attracted to him. That's not Sekai, that's just Kaori.
Now, obviously people may not be okay with having sex with multiple people for multiple reasons - so I'm not judging no one's personal opinions on if they (players) would or would not any character whatsoever. Haruka cheats on her husband, Sara is in constant denial about her son's death and coping with sex and alcohol, Maki has a very specific sexual past - one could find any of these to be a dealbreaker. But, as Kaori, they're all adults. And as all of the above, Kaori also has special circumstances.
I personally don't agree with her being a kid, she suffered a heavy trauma and that has affected her brain, and yet she's able to function, has multiple jobs, provides for herself and learns to live her life and better herself despite her disability. If she were to ever want a romantic relationship, to deny that based on "no, you have a disability and therefore any romantic relationship with you is a line that should not be crossed even if consensual" to my understanding would just be prejudice.
I would not like for her to be taken advantage of, on that we can all agree - but for a person with a mental disability be denied romance when they can take care of themselves, understand and set their boundaries (which she has done in relation to intimate relationships many times over) doesn't make sense for me.