What other potential devil fruits would work with that, anyway (current and theoretical)? Not saying it'll happen, just curious.
The funny thing is because there's multiple different characters which can be used for each number, there's a lot of permutations, syllables and meanings… Especially something weird like Paw fruit where it barely describes the actual power at all and just an aspect of it. . But of the sensible ones
Nikyu = paw (kuma)
Niku = meat
Niko = *elephant (zou zou already exists)
Jikyu = persistence
Jiku = axis/axle
Jiko = accident
Fukyu = uncouth
Fuku = clothes (kinemon)
Fuko = *wolf (inu inu: model wolf already exists)
Tama's fruit might be the tsuke tsuke which is "attach", and that would also fit the pattern though it starts getting a little trickier and requires more nuance in the language than I have.
Monet's fruit Yuki Yuki apparently sort of fits but you really have to stretch it and reverse the numbers, or possibly have a bad grasp of japanese to make it work. Not sure which. At this point I'm fairly convinced that's something a monet fan made up five years ago to argue for her joining and it stuck as a taken for granted myth.
It gets worse if you allow 9.2 to be the word instead, because then you get another dozen options, including Kuni (country) which is where they are now, Wano Kuni, suddenly, ball child, lottery, accident, payment... and some other things... but that doesn't allow for the perfect adding up to Su-ni-go which HAS to be intentional, that's just beyond coincidence.
Then it gets REALLY bad because words can stack into other words in weird ways thanks to how kanji works, but I think Oda tends to keep devil fruits simpler, so...
This of course all gets harder if Oda gets really crazy and stretches, and uses the abbreviation of a word instead of a full word to make something.
My grasp of japanese is nowhere near strong enough to make any real examples though.
So Oda could in theory pull out "this is the watermelon fruit. But actually, melon turns into asparagus, which then turns into eighteen, which is of course two times nine!" so there could be any sort of stretch if he wants it so. (The previous sentence is complete nonsense example, none of those words turn into those things.)