Just thought I would add my 2 cents here. I also have 8 jets on a standalone 1 HP pump but I wish I had a bigger pump. My jets require about 15 GPM each which is a total of 120 GPM. With the head loss I have, even with 2 1/2" pipes, I get about 13 GPM per jet and it is not as strong as I would like. So double check the jet rating to make sure you will be getting enough pressure and flow to the jets for your liking. Some people like strong jets and some weaker.

A variable speed pump would give you some flexibility to choose your strength but they cost over twice a standard pump.

On pipe size, you can actually get away with 1.5" pipes as long as you have parallel runs from the pool to the pad and you use all 2" piping at the pad. So each skimmer, main drain and return has it's own pipe. You can equate the number of pipes with the following equation derived from hydraulics:

Equivalent Diameter = Pipe Diameter * N ^ (2/5) ; where N is the number of pipes

So 2 1.5" pipes is about equivalent to a 2" pipe and 3 is close to a 2.5" pipe.

I think it is a better design to have separate lines to each suction and return port and a ball valve for control reasons but I would still go with 2" lines for each instead of the 1.5" lines to reduce head loss even further.

Some builders like to use a single 2.5" suction line from the pool to pad and a single 2" return line from the pad back to the pool. This however, does not allow you to isolate the main drain into the pump for draining and it is more difficult to control the flow in each of the skimmers.

If your builder is suggesting a single 1.5" line for the suction and return lines (1 each), I might look for another builder since he really does not know what he is doing. But then again, most builders don't. That's why I contracted my own pool.