I don't recommend trying to make the slider title an H1. For SEO purposes, it's best to avoid this. The reason is because the slider would create multiple occurrences of the H1 tag, which search engines DON'T like - it confuses them. It is best practice to have only one H1 tag per page, but it is fine to have multiples of other H tags.

However, if you'd like to have say the first slide use an H1 tag, with the rest H2, there is an addon that allows for control of this. I recommend checking out these:

https://www.concrete5.org/marketplace/addons/whale-parallax-slider...
or
https://www.concrete5.org/marketplace/addons/whale-owl-carousel...