The Greek word Βῆμα (court) has a special meaning for the Corinthians. There was a place in Corinth, capital of the Roman province of Achaia, that had that name. About that place it is said that:
"During Paul‘s stay in Corinth, he was brought for judgment before the proconsul Lucius Junius Gallio Annaeanus, also known as Gallio, on the accusation of conducting illegal teachings. Gallio, however, refused to judge what he considered to be a mere religious dispute among the Jews. According to tradition, the site of Paul s trial was the Bema, a large elevated rostrum standing prominently in the centre of the Roman Forum of ancient Corinth and from where the city’s officials addressed the public." (Read Acts 18:12-17).
The Corinthian Christians must have been quite impressed when Paul told them by letter: “We must all be made manifest before the judgment seat [a form of the Greek word Bema] of the Christ.” (2 Cor. 5:10) They could walk into the marketplace and see the Bema, or judgment seat, where mere men rendered judgment. How much more significant to be judged by the glorified Jesus Christ! (g76 7/22 A Journey to Ancient Corinth).
So, when Paul talks about the Bema of Christ, he is referring to a different kind of Judgement, the one that Jesus will execute over the whole earth.
About the word translated in some versions like: "we must all APPEAR before the judgement seat of the Christ", that word is the Greek verb φανερόω which means "being made manifest", and it is used in the verse that follows:
2 Cor. 5:11 Therefore, since we know the fear of the Lord, we keep persuading men, but we are well-known to God. However, I hope that we are well-known also to your consciences.
So, "appearing before the judgement seat of the Christ" imply much more than a physical position, but being known by Jesus as loyal and faithful. It is not necessary to be in heavens to be judge by Jesus since the Scriptures say that is coming to the earth to judge its inhabitants.
Matt. 25:31 “When the Son of man comes in his glory, and all the angels with him, then he will sit down on his glorious throne. 32 All the nations will be gathered before him, and he will separate people one from another, just as a shepherd separates the sheep from the goats. 33 And he will put the sheep on his right hand, but the goats on his left.