Earliest to transplant?

When is the earliest you can transplant? I was thinking around the 2 week area?? My plants are in 4.5" pots and I plan on transplanting to 1 gallon pots. They are about 9 days old... I want to transplant so I can mix in some perlite into the new soil, cuz what they are in now has no perlite... Thanks!

go for it!

They should be okay, but just be very gentle with them.

I would go right into 3 Gallons man, otherwise you will just end up transplaning again.

I would go three gallons, but I will be flowering early, 6-10" because of the height of my grow box. (roughly 2'9") Plus I don't think I will have enough room for 3 gallons until I flower and determine their sex. So I will just go to 1 gallon for now and then go from there... Thanks guys!