I would check with the studio or gyms you would like to teach at. They may have spinning bikes or Schwinns etc and have a certain certification they prefer. They may also be hosting a certification in the future that you could attend. I am certified through spinning as well as AFAA’s indoor cycling. I have a taken a number of Schwinn workshops as well and love their education.
there are several organizations through whom you can take that certification. If you click on this link https://www.ideafit.com/certifications/indoor-cycling, you”ll see the one here at the IDEA website.
I would check with LA Fitness (if you want to be an instructor there) whether they have a preference for one of them.