If a creature that isn't of the chosen type somehow gets a divinity counter on it, that creature will have indestructible.

If a creature has been dealt damage, that damage remains marked on it until the cleanup step. If a creature with a divinity counter on it has been dealt lethal damage, and later in the turn Kindred Boon leaves the battlefield or the counter is removed from that creature, that creature will be destroyed.

If you somehow control a Kindred Boon with no chosen creature type, its activated ability can't be activated.

You must choose an existing creature type, such as Vampire or Cat. Card types such as "artifact" can't be chosen.

You can't choose multiple creature types, such as "Cat Warrior." A Cat Warrior is both a Cat and a Warrior. It's affected by anything that affects either type and unaffected by things that affect non-Cat or non-Warrior creatures.