What shall we say, then?That Gentiles who did not pursue righteousness have attained it, that is, a righteousness that is by faith
-(Romans 9:30 ESV)
Romans 9 is the hermeneutical grid of many many Christians. Through it, many extrapolate a double predestinarian viewpoint of salvation, which means simply that God has already chosen who will go to heaven and who will go to hell, and He has done this unconditionally. The only way to extrapolate this view from the text is to either read with a double predestinarian presupposition, or to simply misinterpret the text.
In verse 30, Paul starts by saying, "What shall we say then?" which signals he is about to summarize his whole point, which is God is not unjust for not giving His gift to all of Israel because, "they are not all Israel who are of Israel" (Romans 9:6). He is also not unjust for sending those who have not accepted the free gift of God to hell, for they (unbelievers) are vessels of wrath prepared for destruction (Romans 9:22). Paul's ultimate point, therefore, is gentiles who have not pursued righteousness, as the Jews had, attain righteousness by FAITH. Whatever else Romans 9 means, there is certainly no reason to read a double predestenarian viewpoint into it, especially in light of verse 30.
To see a detailed exegesis of Romans 9, go here or here. If anyone has any others to offer, feel free to let me know in a comment.