Options page textarea to populate custom post select field

You can use get_option to get your option values. Below is an example

<?php
$selected_name = get_post_meta( get_the_ID(), 'your_meta_key', true );
$options = get_option( 'your_options' );
// If your names are separeated with comma
$names = explode( PHP_EOL, $options);
?>

<select name="your-select-name">
<?php foreach ( $names as $name ) {
    printf(
        '<option value="%s" %s>%s</option>',
        $name,
        selected( $name, $selected_name, false ),
        $name
    );
} ?>
</select>