He could have received these levels on streamers' contests👍

There was also a time when there were no palace level requirements for the then active achievements.

Yes, I picked up the first eight Pioneer levels soon after the achievement was introduced and there were then no palace limitations.  level nine was introduced later and by then palace limitations existed so that one has been obtained, as suggested above, in a give away although probably the Plarium one forming part of the birthday celebrations.

No doubt the town is an alt but it is curious that the player takes the trouble to fulfil some achievements while leaving it at level six.