Normally references talk about your ability in that subject and if not a relevant subject your other skills such as motivation , writing skills and any of that stuff as well your attendance and punctuality and whether you have had any issues that is not mentioned previously such as a mental health condtion. The fact hobbies hasn't been included is not a big issue unis take into account a large number of factors and would not soley base there decision on a reference as references are only human and can easily make mistakes as well so a uni would not punish the student for this. Try not to worry it should all be okay and good luck