Although he previously stated that the Intel Core i5-powered XPS 15 9570 would get the 97 WHr battery option, Frank Azor has recently revealed that those who want this power pack should "move up to the next config" to get it. This means a US$500-worth jump to the cheapest Intel Core i7-driven model.
https://www.notebookcheck.net/The-Dell-XPS-15-9570-with-Intel-Core-i5-and-97-WHr-battery-no-longer-coming-to-the-US.320108.0.html