Many still know the T9 keyboard from mobile phones with fixed keys in 3x4 design. T9 comes from "Text on 9 keys". Then why 3x4 keyboard? Only the letters count. The additional keys are 0,* and #.
If you want to use the T9 keyboard on the Samsung Galaxy S9, please proceed as follows:
T9 keyboard instead of keyboard on Samsung Galaxy S9
1. Start from the home screen and then open the app menu and continue the settings.
2. Go to "General Administration" and "Language and Input"
3. Navigate from there: On-screen keyboard --> Samsung keyboard
Here you can select the entry "English" under "Languages and Types".
Then you can choose between two different keyboard types: QWERTZ 3x4 Keyboard Now marks 3x4 keyboard to use T9 on the Samsung Galaxy S9.
Now you can write your messages with T9 like in the good old days.