Yes 600w works in a 4x4, yes 8 plants works in a 4x4, yes 8 plants works under a 600w, no a scrog is not the best method.
For a 4x4 area your best options are: 2-4 plant scrog, 4-9 plants regular/short veg, 12-16 plant sog. With 8 plants all a scrog is doing is decreasing canopy area - a canopy like this: ^^^^^ has more area than a flat scrog like this: -------. Scrog is great when trying to make a few number of plants cover a larger surface area than they naturally would not, but 8 plants have no problem covering a 4x4 area even with a short veg.
Here are 10 plants in my 4x4 tent vegged for 2 weeks to 1 month on the day they were flipped to 12/12
Here they are at 6 weeks flower after 4 were removed (this is only 6 plants):
See how it is totally packed? If I had a flat canopy I would have lost a ton of my surface area - 600w lights throw plenty far enough for an uneven canopy in a 4x4 area. And with lower than a 4 week veg you won't have enough time to weave much of a scrog canopy.
Here is my current grow - just 6 plants, 3 weeks from seed and just 1 week flower and the tent is already full - in two more weeks it will be overcrowded. A scrog would condense my buds and promote budrot/pm while likely decreasing yield at the same time. But if you had just two plants Id day go for it. Sorry about bolding - I have no idea why it did that.
Progression - day from seed entering soil - not breaking surface. (65gallon smartpot)
Day 1,5,9
Day 13,18,20
Day 22, 29
Day 32 from seed entering soil:
Day 6 or 7 of flower: