It really depends on how Paul was understanding this. The previous scripture to verse 19 was:
Rom 9:18 Therefore He has mercy on whom He wills, and whom He wills He hardens.
We know that God has mercy on those who are of the family of faith, typified by Jacob. But we do know that God blinds sinners.
2Th 2:11-12 And for this reason God will send them strong delusion, that they should believe the lie, that they all may be condemned who did not believe the truth but had pleasure in unrighteousness.
But based upon whether they act righteously or unrighteously.
Joh 14:21-24 He who has My commandments and keeps them, it is he who loves Me. And he who loves Me will be loved by My Father, and I will love him and manifest Myself to him." Judas (not Iscariot) said to Him, "Lord, how is it that You will manifest Yourself to us, and not to the world?" Jesus answered and said to him, "If anyone loves Me, he will keep My word; and My Father will love him, and We will come to him and make Our home with him. He who does not love Me does not keep My words; and the word which you hear is not Mine but the Father's who sent Me.
The Early Church Fathers likened this to self-blinding.
Iranaeus - Against Heresies - Book 4 Ch 39-End
4. But God, foreknowing all things, prepared fit habitations for both, kindly conferring that light which they desire on those who seek after the light of incorruption, and resort to it; but for the despisers and mockers who avoid and turn themselves away from this light, and who do, as it were, blind themselves, He has prepared darkness suitable to persons who oppose the light, and He has inflicted an appropriate punishment upon those who try to avoid being subject to Him. Submission to God is eternal rest, so that they who shun the light have a place worthy of their flight; and those who fly from eternal rest, have a habitation in accordance with their fleeing. Now, since all good things are with God, they who by their own determination fly from God, do defraud themselves of all good things; and having been [thus] defrauded of all good things with respect to God, they shall consequently fall under the just judgment of God.
Paul can be referring to this blinding when saying "why does he find fault [when God causes blindness]"
The real point we need to look at is whether the story of Jacob and Esau is speaking of individuals and how God saves them. Or that speaking of the symbolism of faith-based salvation, verses works, and the rest. Iranaeus, thought it to be symbolic, speaking of two nations.
Irenaeus Against Heresies. (Cont.)
Book IV. (Cont.)
Chap. XXI. — Abraham’s Faith Was Identical with Ours; This Faith Was Prefigured by the Words and Actions of the Old Patriarchs.
The history of Isaac, too, is not without a symbolical character ... From which it is evident, that not only [were there] prophecies of the patriarchs, but also that the children brought forth by Rebecca were a prediction of the two nations; and that the one should be indeed the greater, but the other the less; that the one also should be under bondage, but the other free; but [that both should be] of one and the same father. Our God, one and the same, is also their God
There is much symbolism in the story. As I mentioned in the OP:
The picture of two nations refers to the promise of where faith is found. As Jacob stole the birthright off his brother, by the will of God. So too did the Church, and Gentiles gain the birthright, although it was originally in the hands of the Jewish nation. We see here the picture of two nations reflecting where salvation occurs, by faith, not by works of the Jewish law.
The following verse need not be talking about individual salvation, but further symbolism in the story of the two sons:
Rom 9:11 (for the children not yet being born, nor having done any good or evil, that the purpose of God according to election might stand, not of works but of Him who calls),
For we know:
Gal 5:13 For you, brethren, have been called to liberty; only do not use liberty as an opportunity for the flesh, but through love serve one another.
We see God calls us via faith, not works, He elects faith as salvations method. He calls us to liberty. If Paul is expounding the symbolism of the passage, and its connection to how a person is saved, not by his works but by faith. It need not be speaking of salvation planned before we were born. For it may not be speaking of individuals.