Technically, you absolutely fall into VWP allowances. You are going on vacation, will not be earning money while in the USA and will be staying for fewer than 90 days (the 90 days is not cumulative during a year - it's simply 90 days per visit).

The question then is whether the Immigration Officer will believe you. In your favor, you have a return ticket and a job to return to. You will not be alone in being someone who used to live and work legally in the States, who has returned home but has made friends and perhaps even has family who remain - so you visit them. I really can't see why there should be a problem.