Is the user you’ve saved data for user 1?
This code:
get_field( 'test_field', 'user_1' );
Gets the data for user ID 1. If you wanted user ID 9 you’d need to do:
get_field( 'test_field', 'user_9' );
For example.
If you’re not seeing the data even in the wp_usermeta
table something else may be going on as well.