Sagos have spiney foliage so hurtful if you brushed against it. I would remove it and replace with a tropical, if your weather allows. I don’t know if it’d damage pool but another reason to remove. It will probably have to (carefully) be sawed off.

As mentioned, the spines on the leaves will hurt anyone who brushes hard against them with bare skin. Some people are even allergic to them. But the roots won't do anything to the pool. They're not good plants to have where there's going to be a lot of bare skin running around.

I think your good for another two century's. This is not one of those pavement lifters. No Cycad is.

I think they make decent bonsai, so you should be fine. If you don't like it, I'd expect that it could be transplanted well, if it is in a planter and a large one like that is probably worth a lot. If you're going to remove it, find it a good home. Sometimes nurseries or landscapers will pay you for big, healthy plants.