Yes.it crashe at 92%, even on beta 1.7.0.3 and even after deleting the world from bedrock version, relaunched Xbox édition, loaded the world, saved it to update the map file with maybe some changes on the save process from latest version of Xbox Édition, and then crash again on Bedrock when converting.
good news !
on my world, i finally succeeded to convert it to bedrock edition, but only by removing every chest in the world by myself.