'The pronoun 'it' refers to the very general concept of football and everything that means historically to the English.
This particular use is in indirect reference to the anthemic song Three Lions by Baddiel, Skinner, and the Lighning Seeds, of which the lyrics to the chorus are:
It's coming home! It's coming home!
It's coming! Football's coming home!
'Coming home' means England winning a major international competition. On Sunday, our women won the UEFA Women's Euro 2025 tournament and in doing so 'brought it home'.