In my view, Acts 9:6 happened after God saved Paul.
Look at it more carefully, and listen to yourself more carefully too. Did Jesus say, "Paul, you believe now, good, you are saved? No, Jesus didn't say that, so you shouldn't say it either. Know what I mean? Be careful to just believe what is written without leaning to the left or to the right or going beyond what is written.
I don't believe that Paul could have understood the Lord unless as a lost man of the flesh.
A lost person must hear the directions and then actually follow the directions.
None of Paul's cohorts understood a thing Jesus was saying to Paul. However, I understand that there is nothing that says directly either way so it is open to interpretation.
No way is it open for interpretation. We are not to do that with the scriptures. We are warned not to do that with the scriptures.
Paul finally believes that Jesus is really the truth. He asks what shall he do, and Jesus tells him where to go to find out what he has to do.
We must believe the word, and the word says it plainly.
For me, Paul's words in Corinthians that state a natural man cannot understand spiritual things supports my understanding of this incident.
The natural man is about a man only concerned about pleasing his flesh. That is about a man who won't even consider what Jesus says because it would mean giving up the sins of the flesh.
It is true that some people like Paul's and Silas' jailer were specifically instructed to repent and be baptized some were not. An example would be the dying thief on the cross.
The thief on the cross confess and repented of his sins on the cross.
also, there is no record of most of the disciple's baptisms,
What? John the baptizer prepared the way. That means he had the people repent of their sins before Jesus could come to them.
Isaiah 59:20
“The Redeemer will come to Zion, to those in Jacob who repent of their sins,” declares the Lord.
Malachi 3:1"Behold, I will send My messenger, who will prepare the way before Me. Then the Lord whom you seek will suddenly come to His temple--the Messenger of the covenant, in whom you delight--see, He is coming," says the LORD of Hosts.
Matthew 3:3 This is he who was spoken of through the prophet Isaiah: "A voice of one calling in the wilderness, 'Prepare the way for the Lord, make straight paths for Him.'"
Isaiah 40:3 A voice of one calling: "Prepare the way for the LORD in the wilderness; make a straight highway for our God in the desert.
however; I think it is safe to assume they were.
Well it isn't just an assumption, because, for instance, the Pharisees and teachers of the law rejected John's baptism of repentance of sins...and they are the ones who didn't receive understanding either. We have to obey to receive understanding. We are told to repent of our sins.