This depends on whether sucking juice out of a fruit is considered as if you are eating the fruit itself, or whether you are extracting its juice. There is a machloket on this as explained, here:
We must now discuss a situation where one only sucks out the juice of
a fruit without actually biting into or eating the fruit itself: Is
this similar to one who drinks fruit juice and recites a “Shehakol”
blessing or should it be considered like one is eating the fruit and
he will subsequently recite a “Boreh Peri Ha’etz” blessing? Indeed, we
find that the Poskim disagree about this matter. The Peri Chadash
proves from the Rambam that sucking is halachically tantamount to
eating, for the Rambam quotes the Geonim as saying that one who sucks
on a sugar cane recites the “Boreh Peri Ha’adama” blessing. Clearly,
sucking is equivalent to eating and not to drinking. Hagaon Harav
Yehuda Ayash and others rule accordingly.
On the other hand, Hagaon Rabbeinu Akiva Eiger and Hagaon Harav Yosef
Yedid Ha’Levi prove from the words of the Tosafot that sucking is
comparable to drinking for which one recites the “Shehakol” blessing.
Thus, according to the opinion that sucking is like eating, you would be allowed to suck out the GJ during the Nine Days, but not according to the 2nd opinion.