Just back from Killarney on Tuesday, and the water is above chart datum...not by much, but yes, above. I believe reported as .1 meter above, yes that's decimal-1 meter.
There were only two low water buoys encountered by us along the way, right at the turn, at the bottom of Beaverstone Bay, at the eastern entrance into Collins Inlet, where it's always shallow. No real issues...
I cannot speak to further west from Killarney to North Channel, nor south of Twelve Mile Bay (Sans Souci), our home marina area, but would think you're fine using chart datum to decide.