Not sure it would have mattered whether your system was logging. The FR24 screenshot shows a unrealistic hex code of 249249 which is variously reported on the internet as a US Navy E-6B or a Royal Navy Sea King!
From the photos it looks like a KC-135. UK Daily Mail suggests an E-6B dailymail.co.uk/news/article … ffled.html which would explain the white colour.
And a quick search for IRON99 finds this: forums.radioreference.com/2337599-post98.html
So perhaps it was E-6B 164405 if callsigns are retained by the same airframe? But having followed the track to Oklahoma, after descending the track is less certain and it vanishes. Although nearby at the same altitude RUFF7 appears - that is supposed to be E-6B 164404. Mysterious.
As to why it was circling? I doubt anyone will say.