The potter in Romans 9 is misinterpreted and misused by Calvinists. Paul was referencing Isa 29:16 and Jer 18:1-10. The Jews Paul was addressing knew these passages. They were in no way saying God chose to have mercy on some, and show wrath to others unconditionally.
Jer 18:6 O house of Israel, cannot I do with you as this potter? saith the LORD. Behold, as the clay is in the potter's hand, so are ye in mine hand, O house of Israel.
7 At what instant I shall speak concerning a nation, and concerning a kingdom, to pluck up, and to pull down, and to destroy it;
8 If that nation, against whom I have pronounced, turn from their evil, I will repent of the evil that I thought to do unto them.
9 And at what instant I shall speak concerning a nation, and concerning a kingdom, to build and to plant it;
10 If it do evil in my sight, that it obey not my voice, then I will repent of the good, wherewith I said I would benefit them.
Paul was not speaking of Unconditional Election in Romans 9. God's mercy or wrath is conditional upon obedience or disobedience.
Strange...
God always has shown His Mercy and grace towards those NOT obeying His ways!
Abraham a pagen, saved by grace of God
Moses saved by Grace, isreal shown mercy from being destroyed
Noah shown havor, gods grace in Flood
Biggest example was God choosing tosend His Son to wicked/sinful people who would end of nailing Him to a cross...
While we were YET enemies to God, Chrsit died for our behalf, Godly for the ungodly...
How is that God waiting to react on how we would respond before offering His Grace?
IF God chose to save based upon our obedience to the Gospel, NONE would ever get saved, but since He initated Grace towards us while we were yet sinners AND disobedient...
Shows that the God we cals worship is the God of the Bible!
So, Calvinists abuse this reference to the potter in the OT to make it say the exact opposite of what it truly means.