it doesn't bother you that the Manuel "recommends 89" even though ti still says 87 is "acceptable".
i would have an internal melt down
I am at 17K miles with at least 15K miles of 87 Octane fuel use, it does not bother me.
It is no longer the 1970's with fixed timing ignition systems. The manual finds it "acceptable" without any other caveat, I am fine with it. Most manual specifications and call outs are for what the vehicle may experience under heavy use conditions. If FCA/RAM had problems with 87 octane at all, they would not even put the moniker of "acceptable" in the manual.
My wife's little 2013 FIAT 500 has the same statement about fuel use of recommending 89 octane and but allowing 87 octane to be use. Never any issue there either in close to 40K miles with nothing but 87 used.
Nothing wrong running 89 out the gate if you so choose.