already doable with these filters / functions

https://docs.wp-pizza.com/developers/?section=filter-wppizza_filter_options
https://docs.wp-pizza.com/developers/?section=global-wppizza-functions
i.e somethimg along these lines

add_filter('wppizza_filter_options', 'my_prefix_my_options');
function my_prefix_my_options($wppizza_options){

/* 
	on pickup , set your other closing times as you wish, 
	below closes shop everyday at 9PM 
	except on sunday where it will close at 8:30
*/
if(wppizza_is_pickup()){
	$wppizza_options['openingtimes']['opening_times_standard'][0]['close'] = '20:30';//sun
	$wppizza_options['openingtimes']['opening_times_standard'][1]['close'] = '21:00';//mon
	$wppizza_options['openingtimes']['opening_times_standard'][2]['close'] = '21:00';//tue
	$wppizza_options['openingtimes']['opening_times_standard'][3]['close'] = '21:00';//wed
	$wppizza_options['openingtimes']['opening_times_standard'][4]['close'] = '21:00';//thu
	$wppizza_options['openingtimes']['opening_times_standard'][5]['close'] = '21:00';//fri
	$wppizza_options['openingtimes']['opening_times_standard'][6]['close'] = '21:00';//sat
}	

return $wppizza_options;
}

not tested as such but should work