Can you please elaborate on the symptoms you are experiencing?
It sounds like you are saying that in your Wi-Fi advanced settings page Wi-Fi control history is showing that the Samsung account is turning on and off your Wi-Fi network. Could you add a screenshot image to this so we better understand the issue your having?
Galaxy S9 SM-G960U
Security Patch Level
November 1st , 2019
yes shows exactly, samsung account turned on or turned off wifi automatically. so i dont know why i see!! i never seen before. and how it possible turn off or turn on wifi. i dont remember maybe i sign in to themes to download theme new or something like that, i dont remember but now i sign out and do same situacion , not changed to today date. its shows 2019-11-18.. samsung account turned on or turned off wifi . i post picture, but this not mine, but something like that issue, on my this screen
shows just Samsung account app icon.
Too simple, what its showing you is apps that have been able to turn wifi on/off automatically without you having to do it manually (yourself). This is due to app permissions, go into your system options but swiping your notifications bar down and pressing on the cog symbol icon, go down to apps in the menu and go into it, once your in the apps menu you will icons at the top right hand side of your screen, one of them will look like 3 dots, press on that and a drop down menu will appear, one of the options will say "App Permissions", go into that. From there you will see a list of apps and the permissions you've granted them on first use of the App. Any App that has the "allow to change system settings" turned on has the ability to turn on/off your wifi as well as perform other actions you might not want them to do. Simply turn that permission off and your good to go. And to answer your question, no you have not been hacked, you just need to make sure to read the permissions that Apps ask you to allow more carefully from now on so this kind of thing doesnt happen again. If you have trouble understanding curtain permissions or would like a more in depth description of the permissions, while your in the app permissions menu you will see an option at the top that says "all permissions", that's not saying that your going to allow all permissions, that just shows you a list of all the possible permissions that apps might ask you for, and if you click on them individually, they give a better description of what that curtain permission does. Hope this helps.
Might be due to either an update to the samsung app, which could include new permissions, or an update from your android version your using or the samsung interface (One UI), which is relatively new and also updating.