Looking to repair a few cracks in the rear rollbar pad. Anyone recommend a vinyl repair kit they were happy with the results?

You can get a brand new pad from AA.

I think once they start to crack, it’s hard to reverse.

If it's not too bad, and you don't need concour results, the hobo fix is
A:
1) small dabs of translucent vinyl adhesive caulk with a toothpick (work it into and under the crack area) and press down,
2) smooth/clean edges with a wet Q-tip or similar,
3) allow to cure overnight, then
4) touch/daub paint with a satin black paint (spray paint in a small plastic cup) or black shoe polish.
Hobo, for sure.
B:
Smack a clever adhesive sticker (some racing team or something) over the whole thing and pretend you're just being cool.
I think what I saw one time was extra wide Flex Tape or Gorilla Tape. Honest....

The cracks will show through the sticker.

Glue some Benjamins on the thing.