Besides these other places, if you’re looking for free WiFi hotspots in Aberdeen you can also try the St. Nicholas area.
In St.Nicholas Square (where there’s M&S and Starbucks) you sometimes can connect to the Free WiFi Aberdeen network provided by the city. (Try the Bratwurst from the kiosk while you’re there!)
Also, if you have a macabre turn of mind, you can find a few free-for-all WiFi networks in the St. Nicholas Kirkyard on the Union Street side. Actually, the Kirkyard (churchyard) is lovely… just be careful of the (bloody) seagulls if you happen to have a sandwich.