In Adam Clarke’s commentary on Romans 9, he argues for that God choice of Jacob and Esau were primarily national1, rather than the unconditional individual election and reprobation. The idea is that God chose to bless the Jews and reveal Himself and His plan of salvation to them, but now God is choosing to bless the Gentiles and call them to salvation as well. But just as the Gentiles could be saved and Jews lost in Old Testament times, so also Jews and Gentiles can be saved now; so national election doesn’t guarantee individual salvation.
Clarke argues that we must understand the whole Old Testament context of the quotes Paul makes, based on Paul’s making use of Esau’s running and the hardening of Pharaoh’s heart, even though Paul’s OT quotations regarding Esau and Pharaoh don’t include running or hardening. Then Clarke argues that Israel’s blessings in verses 4-5 are national, not individual, the election of Jacob over Esau in Genesis 25:22 was national, not individual, the loving of Jacob over Esau in Malachi 1:2-3 was national, not individual, the work of the Potter in Jeremiah 18 is national, not individual and the election discussed in Romans 11 is national, not individual. Thus he concludes the election discussed in Romans 9 is national, not individual.
1 Other non-Calvinist interpretation of Romans 9 include 1) election based on foreknowledge which some of the church fathers held, 2) corporate election and its close cousin and my own view 3) God’s choice of faith as the instrument of justification.