I suppose it depends on what pressure the company operating B787s sets. I passengered on a company B787 when they first arrived and I was keen to experience the much adverised effects of lower cabin pressure. I didn't. The flightcrew had the aircraft pressurised at 8000 ft much the same as my old Jumbo. The reason, fuel efficiency. There may be an ability to seriously reduce cabin pressure but doing so burns more fuel.
Edit to add apparently. I've never been type rated on a B787 so can only report as told.