if you book nine days off work you usually get at least 13 days off work as you have weekends. This way you are only getting an extra 5 days holiday.
NB bank holidays count towards your holiday entitlement. each worker is entitled to 5.6 days annual leave for each day of the week they work. so if you work 5 days you are entitled to 28 days annual leave (5*5.6). This includes bank holidays which for most workers is taken automatically.
you're not really getting anything for free