Agree with Kim's thoughts on depth. 9' is very deep for a 30' long pool, meaning yes, very steep. Especially if you want an area that goes out 4 or 5' some distance. I highly encourage you to map out the desired depths at one or two feet increments along the length of the pool to see if it makes sense. Note that the pool cross-section is not to scale, as noted - not even close to scale.
A few questions:
Is their going to be a diving board or is this just to accommodate diving from the side, or fun underwater swimming?
How far out in the shallow section length-wise, do you want a 5'4" average height US woman to be able to stand? I say that because of parties and such. If you only care about your family then use those heights. That would be the point where the depth is roughly 4' 4-6". A foot or 10" less depth than your height puts the water level below the chin. But don't count children's heights. Pools are about the long-term and kids grow FAST.
Just for reference. Our pool is 8' 6" deep. The pool is 5' deep at the halfway point, 19' in. We have a diving board.