you can change the number of products per page by placing the following code in your functions.php file
add_filter( ‘loop_shop_per_page’, ‘new_loop_shop_per_page’, 20 );
function new_loop_shop_per_page( $cols ) {
// $cols contains the current number of products per page based on the value stored on Options -> Reading
// Return the number of products you wanna show per page.
$cols = 9;
return $cols;
}
or
you can use this plugin to edit products per page visually https://wordpress.shaplakanon.com/product/simple-plugin-edit-woocommerce-hook-using-visual-editor/