Sandy Skin
I can't seem to find anything for sandy skin on a G9 model. I would've thought this would be a thing with how many bikini and beach related things there are on here.There's plenty of wet skin options but nothing for sand sticking to skin? On the arms, legs, chest, butt, etc. all a part of the beach experience.

Comments
It doesn't cover the whole body, but there is a recent freebie that may interest you:
https://www.deviantart.com/smida460/art/Freebie-gagorder-SmidA-sandy-bottom-1200566795
https://www.renderosity.com/freestuff/items/98904/sandy-bottom-daz3d-iray-g9
I can't suggest a complete solution beside SmitA's sandy bottom (which I have to confess doesn't look very gritty to me), but maybe I can suggest an idea of the way to doing it.
I understand the texture maps between G8.1 & G9 are similar (will confess I've never looked in great detail, G8.1 and G9 haven't really been on my radar as I haven't been good enough to be constrained by limitations in G8). If so, possibly you could use the sand material settings in this Linday product: https://www.daz3d.com/dforce-classic-wet-hair-for-genesis-8-and-81-females and apply them to a geoshell you create around G9. If need be, you could alter the textures yourself to cover areas of seams by cloning in a graphics package. As I said, not a complete solution, barely more than an idea of how to do it, but it could work.
Failing that - there is a very good G8/G8.1 solution already pointed to... ;)
Regards,
Richard
I don't believe the sandy skin shown in the promo for that hair is part of the product - if it is, I can't find it in my copy. It's a great hair though.
This is the one with a wet/sandy skin geoshell: https://www.daz3d.com/long-wet-hair-with-dforce-for-genesis-8