I think you're going to need to provide a bit more detail. I don't think there is any established certification for Arduino programmers. I don't think it would be of much value either. In general I don't think programming certifications have much value anyway. That is my opinion, and it's based on experience.
As far as I will say, when evaluating candidates for jobs, the value of a certification is based on the reputation of the authority which issues it, and the demonstrated knowledge of the candidate herself. In my paying jobs, I have primarily worked in the Microsoft world and I have known many people with various certifications from Microsoft. I have great respect for Microsoft as a certification authority, partly because I've done some of the tests but mostly because they are the ultimate authority on their own tools. I also have great respect for candidates with demonstrated skills.
The problem is that one thing does not imply the other, and many people are able to obtain certifications in programming tools and languages, while being unable to actually use those tools or languages for anything practical. Oh sure, they can tell you what a primary key is and explain 18th normal form, but if you give them a data file and ask them to make a table for it, and you come back two days later and they still haven't figured it out... well, you quickly learn that at least in some cases, certifications are worthless. I have met people with certifications who were excellent at the job, and I have met people without any certifications who are excellent at the job. I personally have not bothered to keep up with certifications and I'm still desirable in the job market because I can demonstrate experience and I have a good personal reputation.
So, I would say don't concentrate so much on the certification thing, but concentrate instead on having your students demonstrate their skills. Maybe partner with another local industry and see if you can do something charitable or helpful that will get you noticed and grow your reputation, and most importantly, allow your students to demonstrate their skills. It's a classic win-win situation - you get publicity and your students get experience.