A couple of examples of Sudoku Jigsaws (with non-contiguous regions) which require just 8 clues.
If one considers the set of possible Jigsaw patterns, there are obviously far more than there are Latin Squares.
For N=9, we have 377,597,570,964,258,816 different Latin Squares, which is quite a lot, but tiny by comparison with the number of possible Jigsaw patterns, which is a whopping
Now this includes all possible partitions of the 81 cells into 9 regions of equal size, with no restriction on whether these regions are joined together or not.
I generated over 1,000 random examples (admittedly a drop in the ocean), and found that in EVERY case, an 8-clue Jigsaw puzzle was possible.
When we consider only "conventional" Sudoku Jigsaw's, ie with 9 contiguous regions, that's when the average number of clues required tends to increase, with the standard Sudoku puzzle (17-clue minimum) representing a "worst case" from the minimum-clue perspective (although we know there exist 8-clue jigsaws with contig regions, these are exceptional cases)