Just checked and see Mikey Joe came thru with some lyrics, thank you MJ!!! Nice Job.this tune is absolutely NOT The Girl I Left Behind Me (which is the same tune as the Waxie's Dargle).
Craic is Irish for "fun or good times", and the Craic being 90 says it was a whole lot of fun, or as already said, some very fast fun.
Craic Was 90 recorded by Christy Moore, Paddy Reilly, and a whole lot more including myself.