a better question is what maintenance have you performed so far? getting to be a lot of new owners that are buying these cars at those mileages with no history from before they got it.
per this owners manual maintenance schedule from 2013, they should be recommending brake fluid replacement, cabin filter(very easy to do yourself with no tools), oil and oil filter, engine air filter, and a tire rotation.
https://www.ft86club.com/forums/showthread.php?t=98730
at 60k, you should've had brake fluid, spark plugs, and trans fluid, replaced, and at 75k, the fuel filter is called for replacement...
what you should be doing in this case really depends on how closely the maintenance schedule was followed so far. historically, i've bought a number of cars around 90-100k, and will always do plugs, all the fluids(just a change, never a flush), and then inspect the rest of the mechanicals for other future repairs.
definitely don't feel obligated to go to any dealer for service. independent shops are just as qualified to do all of the routine maintenance, and will be much cheaper.
and just note-- these cars use subaru super blue coolant. it should be very dark blue. if you have anyone change it, be sure to check the color when they're done.