Unfortunately OP provided no references, and I am only aware of Zeichman making this claim - which is not accepted by the majority of scholars (I even doubt Udoh would accept it) and is a minority view, primarily because it is a misreading of the passage in Mark.
Udoh is a historian of taxation in Palestine and has never claimed that no tribute was paid to Rome before AD 70 - which would be a truly bizarre claim -- only that the tribute that was paid was not oppressive, and therefore it would make little sense for Udoh to argue that a debate about taxation could not have occurred prior to AD 70 as if jews were not subject to any tribute at all. So here, the lack of any references in the OP's question prohibits a full answer, as the vague "scholars say" is not a sufficient claim to prove who said what and in which context.
Let's look at the passage:
Mark 12:13–17 (KJV 1900)
13 And they send unto him certain of the Pharisees and of the
Herodians, to catch him in his words. 14 And when they were come, they
say unto him, Master, we know that thou art true, and carest for no
man: for thou regardest not the person of men, but teachest the way of
God in truth: Is it lawful to give tribute[κῆνσος] to Caesar, or not? 15 Shall
we give, or shall we not give? But he, knowing their hypocrisy, said
unto them, Why tempt ye me? bring me a penny[δηνάριον], that I may see it.
16 And they brought it. And he saith unto them, Whose is this image
and superscription? And they said unto him, Caesar’s. 17 And Jesus
answering said unto them, Render to Caesar the things that are
Caesar’s, and to God the things that are God’s. And they marvelled at
him.
First, κῆνσος is a general term for tax. It covers all taxes, not just poll taxes. And the passage is clearly not about any specific tax but the general principle of whether it was a sin to pay taxes. There were examples of these types of taxes throughout the history of Roman administration well before AD 70:
κῆνσος, “tax,” is a Latin loanword (census) that was used in Greek,
Aramaic, and Hebrew (cf. קְנָס qĕnās, DJPA, 497–98). Matthew follows
Mark in using κῆνσος, but Luke uses φόρος, “tribute,” in his parallel
account (20:22) and uses it again in L material where Jesus is accused
of forbidding the Jewish people to pay tribute (23:2). On κῆνσος in
the papyri, see BAG, 431, and MM, 343. The full meaning is enrollment
(ἀπογράφειν) of names and assessment of property for the purpose of
levying taxes (Luke 2:1–5); the word census or κῆνσος alone can mean
“tax.” On hatred of taxes in the Herodian period, see Josephus, Ant.
17.11.2 §308. Following the removal of Archelaus in 6 C.E., Judas the Galilean urged Jews not to pay Roman tribute and incited a revolt (cf.
Josephus, J.W. 2.8.1 §118; Ant. 20.5.2 §102). An event such as this
and the passions it had aroused would still have been felt twenty-five
years later when Jesus was asked about his opinion on whether to pay
taxes to Caesar.
The subject of whether one should pay taxes was widely debated in Jesus' time, with many Pharisees believing it was a sin and Herodians believing it wasn't. This was a pre-AD 70 debate as no one would have it in the context of open war and Herodians ended as a viable political force within Palestine after AD 70 -- The last ruler of Herod survived until AD 92, but they were completely discredited after AD 70 and would not debate with Pharisees after that point as no Pharisee would associate with them. This is something Udoh at least would know.
The Pharisees and the Herodians held to very different views on this
controversial subject. The Herodians (Ἡρῳδιανοί, from Latin Herodiani,
meaning supporters of the Herodian rulers) believed that it was
appropriate for Jews to pay taxes to Rome directly (as in Judea in the
time of Jesus) or indirectly through the Herodian client-rulers (as in
Galilee and Gaulanitis). The Pharisees, or at least those who
approached Jesus, probably viewed the payment of taxes to Rome as
idolatry. At least some Pharisees took this view (and some perhaps did
not, if the rabbinic literature is any guide; cf. b. Pesaḥ. 112b; b.
B. Qam. 113a). One should remember that Saddok the Pharisee was among
the followers of Judas of Galilee (or Gaulanitis) at the time that he
refused to pay taxes to Rome (cf. Josephus, Ant. 18.1.1 §§1–10; J.W.
2.8.1 §§117–18).
So how can Zeichman misread the passage in such an obvious way? Because he is an expert on coinage and he ignores what the passage is about -- the raging debate between the Pharisees and the Herodians as to whether it was a sin to pay taxes, which firmly dates it pre-AD 70 -- and obsesses over the mention of "denarius", as that is his area of study. Moreover it doesn't appear that Zeichman knew about the various tax revolts that happened pre AD 70 and so he thinks that there was no κῆνσος levied even though we have clear examples of it being levied. His research confirmed a large increase in denarii after the first Roman war - as Rome gave coinage to its soldiers and workers and thus after any building project or military presence the region would have more coins. From this banal observation, Zeichman steps out of his lane to conclude, via a type of anthropic argument, that Mark was probably written after AD 70, even though denarii were present in Palestine and circulated at the time of Christ (and well before), but in smaller numbers than after AD 70. The spurious argument that this must have been a poll tax that was payable only with a denarius is simply not present in this passage, which discusses the principle of paying tribute (which we know was being paid), using an example denarius (that we know was in circulation) to illustrate a point that money is the creation of the state but that man is God's creation, and each should be given their due, thus resolving the religious debate about whether paying taxes was a sin.
Thus Zeichman's view is not a mainstream view and is not shared by any major commentary, whether critical or exegetical, of Mark.
Craig A. Evans, Mark 8:27–16:20, vol. 34B, Word Biblical Commentary (Dallas: Word, Incorporated, 2001), 246.