No, the Romans did not care for, nor attempt to colonize Thule/Iceland. In fact, I dare doubt that they knew of its existence at all. Almost no evidence exists in the form of writing and maps to substantiate the notion that individuals from the Roman Empire had a physical presence outside of the Mediterranean, continental Europe, and the British Isles. Scandinavia - though traded with at length from the first century BC onward - is unlikely to ever have had a continual presence of Roman merchants or other individuals in classical antiquity.

This brings us to the question of the coin. How come currency of Roman coinage has been found from Iceland to South China and even Japan? The theoretical reason for this builds on another fact we discussed at the beginning of this answer; namely trade penetration. Though the borders of the Roman Empire were limited at natural barriers, they were reinforced to keep people out, rather than prevent insiders from travelling beyond them. From the 2nd century BC onwards, most Roman conquests were preceded by an influx of traders, brokers, and other travelers. In many ways these 'Roman' individuals (having come from the Republic/Empire does not make one a Roman per se) formed a sort of soft-power vanguard. When and where these individuals were contradicted or antagonised in contending for there interest in a meaningful way, the Roman military was likely to intervene. Good examples of this exist in the form of the campaigns against the Lusitanians (155-140BC), the 6(!) Macedonian Wars, and the campaigns against the mountainfolk of Southern Turkey during the late Republic. Now, since Roman trade penetration was massive in size, scope, and range, it is in a way rather logical that its currency travelled so far and wide.

To add to this, there is a numismatic perspective to be considered. Roman currency from several periods - ranging from early Republic to Late Empire - has archaeologically consistently shown up in hoards and places beyond the scope of the Empire's existence. The likely reason behind this is that the coins remained in circulation even after the decline and fall of the empire or otherwise retained a value as objects made of certain amounts of precious metals.

Viking traders and raiders could thus potentially have acquired these coins in both their peaceful and violent dealings with the coastal populations of the British Isles, Northwestern Europe, or even the Iberian peninsula during the 500-1000AD period.

For sources I have drawn on two works of Adrian Goldsworthy, namely Pax Romana of 2017, and the Fall of the West of 2009