Welcome to the Cake Decorators Q&A

If I cover a cake with ganache but don’t cover in sugar paste,is it ok to store it out of the fridge?

Yes it is but keep it in cake box somewhere cool well away from radiators or foodie smells, chocolate absorbs other flavours very quickly
The ganache may need moistening when you apply the sugarpaste, just brush it with a little hot water enough to make it tacky.