9 of 9 hens laying all laying the same day is entirely possible for a day or two but nobody would expect that to go on every day indefinitely.
3/6 for us today 2 Cream Legbar, 1 White Sport CL, one august hatch mystery hen(doubt she is laying), 1 EE and a Delaware. The Delaware is a machine laid her first egg last Friday and it was probably a store grade XL, 5 in her first 8 days laying now if I could just get her to lay in the box.
The other eggs have all been pretty uniform in color and shape kind of long and pointed on one end, maybe medium to large in a bluegreen and since some days have been two I suspect the CL and/or WSCL rather than the Easter Egger.
Getting about 13hours of light.