I wouldn't mind a casual business relationship! Since he would have moved to Recolle not very long after Yukine his store would have been around for about 2 months or so. And he would be fine with casual conversation and such too, if raising an eyebrow over how many jobs Yato seems to have gone through.

...Then as soon as he finds out this is the guy who was son's gateway bro to delinquency he will stare and judge.