Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified. [Romans 8:30 KJV]
The sinner who is justified is regarded by God as possessing his (God's) own righteousness. This is called 'justification by faith', for it is within the faith of the believer that God sees his own righteousness.
Thus the man who admits his own unrighteousness and casts himself, utterly, on the mercy of God as the only means of ever obtaining righteousness, is regarded by God as possessing his (God's) own righteousness, Matthew 6:33.
Thus is he justified in the sight of God.
Thus the publican went down to his house, justified, Luke 18:14.
He was indeed, saved at that point and up to that point. But there is more to come. There is more to face, there is more to know, there are more battles to be overcome.
But the man is not alone. For God is with him. Evidently, or he would not have come even this far.
He will be saved further. He will be saved to the uttermost, Hebrews 7:25.
For God is in this thing.
And whom God justifies, him will God also glorify, Romans 8:30.
It is certain. It is inevitable. It is incontrovertible.
For God in this thing.
God foreknew him, Romans 8:29, 1 Peter 1:2. God chose him in Christ before the foundation of the world, Ephesians 1:4. God determined this matter, before the man was born. And God shall bring all to pass, according to his own counsels in unanimous determination, Ephesians 1:11, by promise and by oath, Genesis 22:17, and by divine love.
For the publican shall be able to say, with Paul, that the Son of God has loved him and has given himself for him, Galatians 2:20.
And that is salvation indeed.