Should this info be believed? I know that you can use online sources to identify commercial flights; where they are, when they are due to land, etc. Would the public be able to do the same thing with military planes?
Why yes as a matter of fact they can. ADSB transponder data is publicly broadcast and when received and displayed shows the location of all plans with their transponders on.
Here is the web site providing the data, here is a list of military aircraft currently flying with their transponders on. I doubt combat aircraft operating in conflict zones turn their transponders on.
Yes, in most cases.