Do I need to sister this ceiling jost?
The notch at the bottom is fine - not even close to hitting code requirements... which gives you 1/4 joist and that is the best place to notch - near the edge.
You get 1/3 the joist height for holes.   I don't think yours meets that even if you add the inch shaved off on the bottom.   You could sister something over the hole but for something that small your sister would be for aesthetics as the joist is not going to feel any tension near the end like that.