No A350-1000 and A350-900, they do not have the same engines. Both A350 variants are fitted with the Rolls-Royce Trent XWB. However the A350-900 is powered by the Trent XWB-84, and the A350-1000 with the Trent XWB-97.
Long haul
The A350-900 is the smallest variant of the A350 family. It comes in 3 different weight variants: regional, classic and ULR for more optimised usage depending on operators’ needs.