Compare verse 7 with verse 14. No angel is a son. Christ is God. Christ is utterly superior over the angels and everything. Wordly kings many times do not have a righteous sceptre as does Christ.
Many worldly kings abuse their authority.
Yet Christ's righteous sceptre demands hell for sin which Christ paid for for the believers. Christ was anointed by the Holy Spirit. So Christ's joy is above that of the believers. His joy is perfect. He spoke and they were created.