Flashing Chinese N9 with European FW is possible but gets tricky at times due to the cmt part of the rootfs.bin file; if its a 001 pr legacy Chinese variant you shouldn't have any issues but if its a 006 or 009, I can't remember which exactly, then you may or may not face an issue...

Maybe contact the seller and ask for the FW version number?

Chinese & Finnish HW may not really differ; there are some who report Finnish sets have better buttons while others say the same about Chinese sets but its mostly about the batch so you won't have an issue if its original... If its a newer production batch you are in pretty good footing too...