does this amulet is balanced [on hold]

In a recent campaign that I am running one player is priest of war, I made a special quest for him, the quest start with his god making a request. If completed he will receive an amulet.

I am trying to give him the feeling of being backed by a god. he is lvl 4. I want to know if this is overpowered or underpowered for his level.

amulet of Honor

The amulet harbor the player god sign, this amulet cannot be hide. If the player try to hide it or lies about his faith the amulet disapears.

need Attunement,

+1 force,

avantage on save based on charisma,

1/day (1 hours) (renew at dawn) (target self) a bright ligth (9ft) irradiate from the player, in this area: undead are desavantaged on attack and everyone attacking undead is avantaged. after 9ft The light is softer and allow to see up to 24 ft.

1 charge max (every dawn launch 1d10 on 10 gain a charge), launch benediction for one hour do not count as concentration spell.