Yes,
Ask him about cost over runs due to cave-ins or bedrock. Also I don't know where your water table is, but does he have a plan for pumping water out of the pool if it rains heavy or you get water seepage from somewhere.
Do you have your rebar and gunite crews lined up? This should all be a 1-2-3-4 process. Dig, rebar, rough plumb, bond, inspection, gunite. This can all happen in 3-4 days if lined up properly. This will minimize your exposure to rain and/or cave-ins.
Do you have your permits lined up? In Louisiana, I only needed a basic building permit for site location and an add-on electrical inspection for proper bonding of the pool cage and light fixtures. I'm sure it will be more strict in California. Take pictures to document your bonding wire is installed properly in case they question it later.
Do you understand what electrical bonding is? And what code requirements are for your area?
Who is doing your rough plumb? Are you installing a double main drain for safety? Probably code...
I used a 2" suction side and 2" supply side loop. The actual return eyeball penetrators necked down to 1 1/2"
Do you know the difference between schedule 40 PVC fittings and DWV fittings? I almost made that mistake in the beginning...
Buy the BIG cans of glue and primer, you'll use alot. Take the time to scuff/clean/prime the fittings properly.
On the day of the dig and rebar install. Have a couple sets of drawings available to pass out to the subs. Carry a tape measure in your pocket and back check what they are doing and digging. I insisted on the usual 3/8" rebar cage for the main pool shell and 4 rods of 1/2" rebar in the bond beam. They referred to this as a commercial tie. Make sure the skimmers are level and set properly. And that they shoot the gunite around the lower skimmer body itself. they should know this already.
One the day of the gunite shoot, carry the same tape measure AND a small level. Make sure any built in stairs and benches are carved level. I caught them several times on this one.
If you are including an autofill/overflow it needs to be rough plumbed in now. You can add the working parts in later, but the penetrator needs to go in now.
Same for a booster fed robot cleaner...if you want one later, put the penetrator in now.
Think about your light niche placement. You want the lights facing away from wherever your seating/viewing area would be at night. So you don't have a glaring light shining at you. Make sure they properly box in around the niche and wire it securely to the rebar cage. My niches got bumped around alot during the gunite shoot. It almost caused a problem.
Make sure the light niche has at least a 3/4" conduit hub. 1/2" is too small to pull wire easily. The top of the niche should be at least 18" below water level. Remember the electrical conduit needs to be glued properly too. It has to be water tight to above pool water level at the panel.
Read all your equipment owners installation manuals. The subs generally know how to do it, but they'll cut corners if they can.
It's all about the planning. Hope this gives you some ideas...
Jim