Harry's BGxT does produce excellent fruit. I have a seedling from this tree that will produce its first fruits this year.
First, zone 9a/b will require significant cold protection. A greenhouse will be required to get this to fruit.
Second, jackfruit does not come true from seed. I have fruited a few seedlings and the resulting fruits are nothing like the parent. 2 are good, 1 might get removed. Just buy fruit and plant the seeds. It will be cheaper and if the fruit was good, you have just as good of a chance of getting a tree with good fruit.
Third, if you are going through all the trouble, you should seriously consider a grafted tree so you know all your hard work is going to produce a fruit you like.