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

146,413,934,927,214,422,927,834,111,686,633,731,590,253,260,933,067,148,964,500,000,000.

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)