Fenerbache is the other side of the Bospherus it seems. Don't know where to start with Istanbul.
I go to Istanbul twice a year for work conferences and we generally stay close to the Besiktas stadium on the European side of the city. Staying around the Sultanahmet and Tamsin square areas makes most sense for the big tourist attractions. From Istanbul’s main airport this is a 45 minute journey on a good day.
The Fenerbahce stadium is on the Asian side so some people may want to stay over there to avoid the mad city traffic. There is an airport on that side too - don’t know the name but code is SAW - and obviously better if you want to stay nearer the stadium. Apparently a taxi can take an hour to get to the stadium from the European side unless you go mid afternoon. I’ve been past the stadium en route to a steel mill and there’s a big dual carriageway which goes past it but apparently clogs up on match days.
One option is simply to get a ferry from the European side to the Asian side ( I think it’s Karakoy to Kadakoy) as it s very cheap and takes 10 minutes. Apparently you can then walk to the ground in 20-30 minutes. I don’t know how late the ferries run for the return trip.
My guess is that the police will run shuttle buses from somewhere on the European side and it will be like Warsaw, meaning they leave 3 hours before kick off then keep you in for an hour after the game providing the full joyless European defeat experience 😉
I’m back over there on 15 October so will get more info while I’m there.