In Keith Schooley's Article: Romans 9: An Arminian/New Perspective Reading, he skillfully uses the OT to explain Romans 9. Paul refutes "those Jews who would say that, if Paul’s gospel were correct, then “God’s word had failed” (9:6). His response to them is that God had never made the unconditional promises, based either on “works” or ethnicity, that they were claiming. God sovereignly chose Isaac over Ishmael; He sovereignly chose Jacob over Esau; and by implication, He can sovereignly choose on the basis of faith in Christ, as opposed to works of the law or ethnicity."
Keith has an interesting take on hardening. Since both Pharaoh and God are said to harden Pharaoh's heart, Keith sees various roles in the hardening process. God provides the impetus for harding and Pharaoh responds by hardening his heart. Regerading the objector in Romans 9:19, Keith explains the objection as "the questioner is asking why faith in Christ should be necessary. That is, how can God blame the Jew for expecting to be among the chosen people because he’s a Jew—in other words, because he’s descended from Abraham and because he’s kept (in a relative sense) the Law? How can God blame the Jews for failing to come to faith in Christ, since faith was not what the Jews were led to expect to be the criterion of election?" Keith then explains that vessals of mercy and wrath are dynamic, not static, groups.