Signal 9 is one of the biggest issue faced by Android 12 users, because of this issue termux users were unable to use termux as Android PHANTOM PROCESS kills the app, but don't worry, In this article we will fix that.
First of all make sure that you have latest version of Termux installed, you can get it from here.
Once you have that, execute following in Termux
pkg update -y ; pkg install android-tools -y
Then go to your device settings -> about and click 7 times on build number, This will enable developers options.
After that just go back and click on system -> developer options, here you will find a options for wireless debugging. Just click on that and enable it.
Then you need to split your screen with that settings and termux. Then click on pair with pairing code their and you with get a pop up where a IP:port is given.
Next go to termux and execute following
adb pair <IP>:<Port>
replace ip and port with the ip and port given in that popup.
Then execute following to connect with it
adb connect <ip>:<port>
replace ip and port with the once given in wireless debugging.
Once you do above step, you will get a message that "connected".
After that execute following
adb shell "/system/bin/device_config set_sync_disabled_for_tests persistent; /system/bin/device_config put activity_manager max_phantom_processes 2147483647"
and that's it, Now you should not get that signal 9 issue.