Friend, this teaching is woefully wrong. The notion that this refers to original sin is inflicted upon the text, not drawn from it. In fact, Paul spends the bulk of Romans 2 establishing who and why all are concluded under sin:
Rom 2:1-6 NASB
1 Therefore you have no excuse, everyone of you who passes judgment, for in that which you judge another, you condemn yourself; for you who judge practice the same things. 2 And we know that the judgment of God rightly falls upon those who practice such things. 3 But do you suppose this, O man, when you pass judgment on those who practice such things and do the same [yourself,] that you will escape the judgment of God? 4 Or do you think lightly of the riches of His kindness and tolerance and patience, not knowing that the kindness of God leads you to repentance? 5 But because of your stubbornness and unrepentant heart you are storing up wrath for yourself in the day of wrath and revelation of the righteous judgment of God, 6 who WILL RENDER TO EACH PERSON ACCORDING TO HIS DEEDS:
Rom 2:12-16 NASB
12 For all who have sinned without the Law will also perish without the Law, and all who have sinned under the Law will be judged by the Law; 13 for [it is] not the hearers of the Law [who] are just before God, but the doers of the Law will be justified. 14 For when Gentiles who do not have the Law do instinctively the things of the Law, these, not having the Law, are a law to themselves, 15 in that they show the work of the Law written in their hearts, their conscience bearing witness and their thoughts alternately accusing or else defending them, 16 on the day when, according to my gospel, God will judge the secrets of men through Christ Jesus.
Paul thoroughly establishes that each person's own sin & deeds condemn them, not the sin of Adam. In fact, Adam is not mentioned either in Romans or in the passages from Psalms that Paul quotes in Romans 3:23, nor in Romans 8.
This is imagined, not born from the text. No where does it describe Adam or the concept of original sin... actually it painstakingly constructs quite the opposite picture. The notion that the tense construes the opposite meaning from the actual words of the text is such a stretch that it strains credulity to the point of breaking. A number of other possible meanings that agree with the text itself are present, so there is literally no reason whatsoever to draw that meaning from the text... and in fact... an abundance of reason to draw the opposite conclusion.
If it meant that "all had sinned" applied perpetually to all people of all times, that would be warranted. But to impose the meaning that this referred to Adam's sin is completely extra-textual, and far beyond the scope of what could rationally be accepted from the text itself. My friend, I'm sorry, but it just doesn't speak of Adam in any way, shape, or form.