I also have a niello 900 and during the seedling stage, I keep it at about 110 cm for the first week of life, then I gradually lower it until I reach 50-60 cm and maintain that distance until harvest.
I’m assuming that’s not an actual 900W fixture but more like 100-200w.
It will probably be fine for seedlings - it’s got a lot of blue in it.
I’d hang at 36” just to be safe and adjust lower if they’re stretching too much