No, because in English the Present Perfect (have been) is not used for a specific finished time, even with no date.
Why isn't it where were you at this time? Correct, how are you supposed to know when это means this or that?
Without context I'm notnsure why 'Where were you that time' is incorrect
Why is it это время and not эта время? I thought that время is feminine, so it seems logical to me that i should conjugate это accordingly.
Why is it not где ты был в этом время? I thought you should use the prepositional case after в which should be этом.
Prepositional would be вре́мени. But I understand your confusion, in my language it can also be locative (in addition to the accusative) which corresponds to prepositional.
There is actually
в режи́ме реа́льного вре́мени ― (in) real time
в ско́ром вре́мени ― soon
But not as in saying at which exact time something happens. It would be good too hear from the natives.
In an informal sentence, (incorrect but commonly used in speaking english with friends) i have had people say "Where you at / where are you / where are you at" so, for common informal american english, "where were you at," is said, 'at' referring to location and not time.
People in america still say "Where are you at," as well as "Where are you."