What are the file names for Android 9? I've found
com.sec.android.soagent and
com.wssyncmldm
Which one is responsible for Android OS OTA updates? I guess the second one
Your question makes little sense.
File names for Android 9? And your phone is a Note 7? If so, did you install a custom rom based on Android 9? (Some Lineage OS unofficial developers were working on that.) If so, why would you fear the N7 Poison Pill Update when using a custom rom?
If you are using the stock firmware on the N7, why are worried about the Poison Pill Update? The last Poison Update was released in Jan 2017 -- nearly 3 years ago! That Poison Update has been retired. It is unlikely that a 'free range' N7 would get hit with it now (at least not as an OTA from a US Carrier).
If you are using a N7 with stock firmware (aka rom) and worried about the Poison, it is easy to avoid it. I am still using the stock v6.0.1 on my Note 7 since Sept 2016. I dodged all Poison Updates by using a Debloater Tool found on XDA. That tool runs from a PC while the N7 is connected. It allows the user to disable virtually any package. I frooze all packages that would allow the Update to kill my N7. Plus I disabled all Bloatware from Sam & ATT, especially all instances of KNOX. I never had to worry about the Poison thereafter ... nor do a thing more.
The tool is very easy to use ... IF you know what packages to disable. Somewhere on my PC is a list of all the N7 packages I disabled. If you disable the wrong packages, you can soft brick your N7. And I suppose that is what your question wanted to know.
The biggest concerns about the N7 at this date is the battery wearing out from use and the Android 6 becoming too outdated. Those issues are resolved by replacing the battery and flashing a suitable ROM ... but both actions are not for the amateur hacker to perform.