Melf’s Minute Meteor Impact Radius

The Melf’s Minute Meteor spell states:

" Once a meteor reaches its destination or impacts against a solid surface, the meteor explodes. Each creature within 5 feet of the point where the meteor explodes must make a Dexterity saving throw"

This seems like a fairly easy ruling for when choosing a point, choose a point in between four squares and any creature in those four squares need to make a saving throw like so:

Melf Minute Meteor Point Impact Diagram

However, how does this interact if if impacts a singular creature in the middle of a square? Does only that creature make it because only that creature is fully within 5 feet or do the creatures in the 8 surrounding squares also need to make it (reference pics below)?

Melf Minute Meteor Square Smaller Impact Diagram Melf Minute Meteor Square Larger Impact Diagram