To them belong the patriarchs, and from their race, according to the flesh, is the Christ, who is God over all, blessed forever. Amen Romans 9:5 English Standard Version
There is no punctuation in the Greek. Only experts could accurately translate the original manuscripts into English. In this particular verse, it seems that, along with accepting the translation of those who knew Ancient Greek, context is the way to determine with any degree of certainty what the original writer intended.
According to their site, the Berean Greek New Testament was developed to reflect the best and earliest manuscripts.
Here is how Romans 9:5 reads in the Berean Literal Translation:
…whose are the patriarchs; and from whom is Christ according to the flesh, being God over all, blessed to the ages. Amen
As to context, the passage says:
9 I am speaking the truth in Christ—I am not lying; my conscience bears me witness in the Holy Spirit—2 that I have great sorrow and unceasing anguish in my heart. 3 For I could wish that I myself were accursed and cut off from Christ for the sake of my brothers, my kinsmen according to the flesh. 4 They are Israelites, and to them belong the adoption, the glory, the covenants, the giving of the law, the worship, and the promises. 5 To them belong the patriarchs, and from their race, according to the flesh, is the Christ, who is God over all, blessed forever. Amen.
In this passage, Paul is lamenting that the Jews or Israelites do not know Christ. Through the Israelites, God teaches mankind of the faithfulness of God, the assurance that His promises never fail, and that the children of the promise are counted as offspring. Paul then reveals Christ, the person Paul wants the Jews to come to recognize and accept, in verse 5. Paul is referring to Jesus. (The Greek text or interlinear of 9:5 is found at Bible Hub.)
It seems to me that the ESV rendering is more accurate than the KJV. The KJV reads:
Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen.
Nearly all translations agree with the ESV above. Of course Watchtower’s NWT disagrees. I find no justification for their dividing the verse into two sentences to take away this statement of who Christ is, but that is what they did.
Below is the commentary of Henry Matthew on the verse.
To the preceding the apostle now adds two more prerogatives: theirs are the fathers — They are the descendants of Abraham, Isaac, and Jacob, the ancient patriarchs, and other holy men, who were great in the sight of God, and to whom he made many great and precious promises, in which their children also and children’s children were interested. And of whom — Of which Israelites; as concerning the flesh — That is, in respect of his human nature; Christ — The expected Messiah; — came. This plainly supposes another nature in Christ, according to which he came not from the Israelites. And this can be none other but the divine nature; which, in the sequel of the verse, is expressly attributed to him. The apostle reserves the mention of Christ’s descent from the Jews for the last of their prerogatives, as being the greatest of them all: who is over all, God, &c. — The apostle gives this, so highly honourable a testimony to Christ, because he was so vilified by the Jews; thus making up that great breach, so to speak, which they had made on his name and honour by their unbelief, and wicked rejection of him. He is said to be over all, 1st, Because, as he was God-Man and Mediator, all power was given unto him in heaven and on earth, Matthew 28:18; all things delivered into his hands, and put under his feet, John 3:35; 1 Corinthians 15:27; the Father giving him a name above every name, Php 2:9; and constituting him his great plenipotentiary, to transact all things relating to the whole creation, especially angels and men; to settle the affairs of heaven and earth for eternity. And more especially, 2d, Because as God, possessed of true, essential deity, he was in union with his Father and the Holy Spirit, supreme over all, and consequently blessed for ever — Which words he adds to show, that a far different measure from that which the Jews had hitherto measured out unto Christ, was due to him from them, as from all other men. No words can more clearly express his divine, supreme majesty, and his gracious sovereignty over both Jews and Gentiles. The apostle closes all with the word, amen — An expression commonly used for a serious confirmation of what is said immediately before, together with an approbation of it; sometimes also importing a desire for the performance thereof. Some would persuade us that the true reading of this clause is, ων ο επι παντων θεος, whose is the God over all; because by this reading, they say, the climax is completed; and the privilege in which the Jews gloried above all others, (namely, that of having the true God for their God,) is not omitted. “But as this reading,” says Macknight, “is found in no copy whatever, it ought not to be admitted on conjecture.” Thus also Doddridge: “How ingenious soever that conjecture may be thought, by which some would read this, whose is the God over all, to answer to, whose are the fathers, I think it would be extremely dangerous to follow this reading, unsupported as it is by any critical authority of manuscripts or ancient quotations. Nor can I find any authority for rendering Θεος ευλογητος εις τους αιωνας, God be blessed for ever. I must, therefore, consider this memorable text as a proof of Christ’s proper deity, which, I think, the opposers of that doctrine have never been able, nor will ever be able to answer. Though common sense must teach, what Christians have always believed, that it is not with respect to the Father, but to the created world that this august title is given to him:” that is, that he is said to be God over all.
Paul is telling us that Jesus is God over all! This agrees with so many other Bible passages and it seems clear to me.