I don't think I understand the question. Are you suggesting that you don't believe that Paul's message (i.e. salvation by grace) is not based on Calvary? That certainly is not a distinctive of Acts 9 Dispensationalism and simple word search yields lost of verses where Paul talks about our having been crucified with Christ. Where else was Christ crucified besides at Calvary?
Romans 6:5 For if we have been united together in the likeness of His death, certainly we also shall be in the likeness of His resurrection, 6 knowing this, that our old man was crucified with Him, that the body of sin might be done away with, that we should no longer be slaves of sin.
That single passage alone is the gospel of grace in a single sentence!
How does that not answer your question? (I think it might have taken me 10 seconds to find that verse, by the way. I'm not bragging, I'm just saying it wasn't hidden or difficult to find.)
There are many other passages like it...
1 Corinthians 1:13 Is Christ divided? Was Paul crucified for you? Or were you baptized in the name of Paul?
1 Corinthians 1:23 but we preach Christ crucified, to the Jews a stumbling block and to the Greeks foolishness,
1 Corinthians 2:2 For I determined not to know anything among you except Jesus Christ and Him crucified.
1 Corinthians 15:12 Now if Christ is preached that He has been raised from the dead, how do some among you say that there is no resurrection of the dead? 13 But if there is no resurrection of the dead, then Christ is not risen. 14 And if Christ is not risen, then our preaching is empty and your faith is also empty. 15 Yes, and we are found false witnesses of God, because we have testified of God that He raised up Christ, whom He did not raise up—if in fact the dead do not rise. 16 For if the dead do not rise, then Christ is not risen. 17 And if Christ is not risen, your faith is futile; you are still in your sins! 18 Then also those who have fallen asleep in Christ have perished. 19 If in this life only we have hope in Christ, we are of all men the most pitiable.
2 Corinthians 13:4 For though He was crucified in weakness, yet He lives by the power of God. For we also are weak in Him, but we shall live with Him by the power of God toward you.
Galatians 2:20 I have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me.
Galatians 3:1 O foolish Galatians! Who has bewitched you that you should not obey the truth, before whose eyes Jesus Christ was clearly portrayed among you as crucified?
Galatians 3:13 Christ has redeemed us from the curse of the law, having become a curse for us (for it is written, “Cursed is everyone who hangs on a tree”)
Galatians 6:14 But God forbid that I should boast except in the cross of our Lord Jesus Christ, by whom the world has been crucified to me, and I to the world.
Philippians 3:10 that I may know Him and the power of His resurrection, and the fellowship of His sufferings, being conformed to His death, 11 if, by any means, I may attain to the resurrection from the dead.
I hope that answers your question.
Resting in Him,
Clete