skyrim is a offline game, so i am pretty sure you cant get banned:)

0.00001% of getting banned for modding an offline game.

Chances of getting banned for modding a singeplayer game are very low, as it doesn't interrupt other players. You can still get banned for modding, don't make it too obvious, level 99 is okay, but don't change your level to like 100 or 1337, people can see that on your profile and you could get reported, but if you max out all of your stats, you should be fine, I've been doing it for a while and I have gotten no ban or warnings.

EDIT: If your going to mod your gamerscore, I would suggest not doing that, I did mine up like 1000G and got banned & gamerscore reset, but you can mod your game, since it's offline.

Don't mod your gamer score it will get you banned

The account is level 81 but stats are maxed and it has 999999 gold and all that stuff.

Slapyoblubba wrote The account is level 81 but stats are maxed and it has 999999 gold and all that stuff.

You should be just fine, just don't put your level to like 100 or 1000 since people can see your level on your profile, your good to mod anything else though.

What if the save gets me a few achievements? Would i get banned for that?

There is almost no chance of you getting banned unless someone reports you (which no one should)

Slapyoblubba wrote What if the save gets me a few achievements? Would i get banned for that?

If it does, which I don't think it does, but it might, the gamesave will initialize them as real achievements, since it's in your game's data, you most definitely won't get banned for that.