Is it OK for bushes to touch the house and fence?
It shows a lack of care for the home. Bushes against the home or a wood fence are an entrance point for pests (termites, ants, etc). It also adds more wear and tear from abrasion that you wouldn't have from just the sun and rain. And for a buyer, a bush growing against the home could be hiding a problem.

So if you want to make it look as if you've been caring for the home, I'd trim it back before the buyers see it. And for your next home, I'd recommend trimming them back as well, so you are actually taking care of your home and not just making it appear that way before the sale.