Xilinx has a large range of FPGA's chips. Why is VU9P the preferred one at this stage? Is it due to the larger than norm Total Block RAM?
The VU9P is the chip Xilinx has chosen to use in their VCU1525 boards as well as their VCU118 dev boards. The chip used for the dev boards is usually a mid-line chip with good yield, and the volume means it almost always has a better price to performance ratio than any other chip.
Actually I got a quote from Bittware on their VU13P setup, and in theory the ROI was (surprisingly) a little better than the VU9P, but it is irrelevant, because unless there is some type of innovation, it is currently not possible to use anywhere close to all the logic on the VU13P, as this would burn 700W+, and the package and BGA pins can't withstand that power level. It is possible that some type of workaround will be found. Until then the VU9P is the biggest feasible FPGA.