2nd try at AGP

You can back fill but it may void your pool warranty. If your willing to forgo that, paint the walls and posts to be buried with a metal sealer. It’s been found that backfilling will decrease the life of the wall but only by a few years, depending on conditions. The real important issue is the pressure of the backfill against an empty pool. You want to backfill with something that will compact and hold its shape. Like clay or slurry(google pool backfill slurry). That way if you have to empty, the dirt stays put and doesn’t shift. You don’t want to back fill over two feet either. Maybe three depending who you ask. Slope the back fill away from the wall. Use a drainage system at the base. If you take all the precautions, the pool will be fine for several years. The downside is always the possible implosion when you drain it and you can’t see any problems with the wall, track and posts if they develop if covered in dirt. Topsoil won’t compact properly without a slurry mixture. I’d say you are only going 6 inches deep it’ll be fine for the most part but you basically need to build a cast with dirt, clay, sand, and Portland cement if needed. Ideally, don’t backfill, cover the hole with a deck and put in drainage. I saw a pool where they just put huge rocks around the dug out and added clay dirt around that. How the dirt doesn’t wash out is beyond my comprehension but that does help control the pressure against the wall.

My pool has been sitting like this for 6 years. There is a drain pipe buried in there. That’s about it. I couldn’t ever decide if I wanted to back fill or build a deck. So I did nothing. No one sees it but me. The biggest issue with me back filling is if have to put up a fence to keep elk out. I’m out in the county so I’m not required to have a fence. Just gates and locks for decking.