In verse 8 we have the aspiration of the psalmist for Christ to judge the earth and to inherit the nations: "Arise, O God; judge the earth;/For You will inherit all the nations." John 5:22 tells us that God has given all judgment to the Son, and Psalm 2:8 reveals that God has given the entire earth to Christ as His inheritance. Therefore, the word in 82:8 applies to Christ, the One appointed to judge the earth and the One worthy to inherit all the nations.
Satan's plot is to take God's habitation in possession through the nations who conspire against God's hidden ones (83:2-12). Psalm 83:3 says, "They devise crafty counsel against Your people,/And conspire against Your hidden ones." Today we, the believers in Christ, are God's hidden ones, and the worldly people do not know us. However, when the Lord Jesus comes back, the hidden ones will become the manifested ones. Today is the time for us not to be manifested but to be hidden.
Finally, in 83:1, 13-18 we have the psalmist's prayer for God to deal with the nations that they may know that God alone is the Most High over all the earth and that they may seek His name. This will take place in the millennium, the time of restoration.