Depends on a lot of things really.
Are you only interested in gaming performance, or do you do some professional work that could make use of the extra 2 CPU cores the 9700F gives you?
How much of a difference is there in price between the 3 options?
For me, a 9400F is £130, a 9500F is £140 and a 9700F is £230. I don't regularly use Lightwave, Adobe After Effects, or any other professional software where the 9700F would make a difference..
So for my needs, the 2 extra cores and 5% clock speed increase for £90 is definitely not worth it for the 9700F, so I would go for the 9500F
As for "will I even notice any difference in games" over the 9100F? Probably not, no. All you are doing is going from 4 very fast cores to 6 very fast cores. Most games don't and can't make use of more than 2 cores, so I doubt you'll see any changes in games.
The correct option is to upgrade your GPU, but that's not possible right now.