I agree - it makes absolutely no sense to having a certification program or starting to hand out certificates before guidelines exist

A preliminary step to such a program would be (for the ACA, perhaps in concert with its members and representatives from the vendor community) to develop and "responsible practices" guidelines.
The acceptance of the guidelines rests ontheir validity (do what they espouse truly reflect priority responsible practices by vendors?), implementability (are they practical and reasonable for the average vendor who cares?), and the participation of those impacted by them in their development.
Ask yourself: What are the things that a vendor can do to act in a responsible way? What are irresponsible practices that you commonly see?
We're not talking about whether a vendor stocks rare, wild cichlids. We're talking about whether the store commits to acting in responsible ways. Experienced hobbyists use these criteria to (mentally) assess a vendor (Me to myself: "The red devils are labeled as red terrors"...and their tank is filthy"). The vast majority don't have the experience or background. This is just formalizing what goes on in our heads...
The cost of such a program would be primarily to defray the costs of running such a program... and (of course) 100% would go to the ACA, which is a 501c3 not for profit. Perhaps select vendors that support the process of creating the guidelines could have their fees fees waived? There are a lot of operational details to be worked out... but the idea appeals to me because it actually does something to define the problem and proposes practical things that vendors can do to address being responsible. It also seeks to strengthen and support LFS and vendors who act responsibly...and promote and spread the ACA brand.