He is reigning now upon the throne of David. 1 Cor 15:24-26
24 Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power.
25 For he must reign, till he hath put all enemies under his feet.
26 The last enemy that shall be destroyed is death.
At His resurrection and ascension He occupied the Davidic throne as the Son of David as promised according to Peter Acts 2:29-33
29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day.
30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;
31 He seeing this before spake of the resurrection of Christ, that his soul was not left in hell, neither his flesh did see corruption.
32 This Jesus hath God raised up, whereof we all are witnesses.
33 Therefore being by the right hand of God exalted, and having received of the Father the promise of the Holy Ghost, he hath shed forth this, which ye now see and hear.
Your first sentence has not happened yet, sit at my right hand till I make your enemies your foot stool.
The right hand of God is not David's throne, it suggest power but not David's throne.
We are just beginning and not at the end.
People still die...so no this has not happened yet.
Im sorry saint but I dont agree to your understanding of any of this.