Almost every King Kyiv/ Kyiv Rus was a Viking. The last Viking King of Norway was also the last King of Kyiv from what I understand.
They fought with the Turks for 100's of years. It wouldn't surprise me if this clothing was not just something they came across on a raid or purchased.
Svyatoslav Igorevich (Sveinald Ingvarsson) was arguably the last ruler of Rus who was a pure-blooded Varangian (Viking), and mostly adhered to their customs - but, notably, he already used the Slavic form of his name predominantly, not the Norse one. His wives appear to have been Slavic, and his firstborn son had a Slavic name.
One of the other sons, Vladimir (Valdamarr), was still a Viking enough to go seek - and get! - the help of his Viking relatives in Scandinavia to overthrow his brothers. But after converting himself and the country to Eastern Christianity, arguably, he finally severed that link. His successors were definitely not Vikings in any sense, although they did marry their daughters into Scandinavian royalty, among others.
The Varangian Guard (personal bodyguards to the Byzantine Emperor) dates back to the 10th century. They were 'vikings' on loan from Kyiv Rus to the Byzantine Empire. There was much more cultural cross pollination than most people who have anglo centric view of history realize.
They fought with the Turks for 100's of years. It wouldn't surprise me if this clothing was not just something they came across on a raid or purchased.