Just because you might be interested, if you work your build so that you can take your 3rd or 5th level of Master of Nine at level 17 and an even Swordsage level at 18, you can get up to 8 9th level maneuvers by 20.

17: Two 9th level maneuvers learned by Mo9 = 2 total
18: One 9th from Swordsage level; one from replacing maneuvers at even levels; one from Martial Study = 5 total
19: One from Swordsage level = 6 total
20: One 9th from Swordsage level; one from replacing maneuvers at even levels = 8 total

Your maneuvers/stances known might not be 100% optimized because of prereqs, but w/e.