Redistilling would require a lot of equipment and knowledge. The oil is not soft because of moisture, it’s soft because there is too much mother liquor with it I’m assuming. Vacuum will not help to solidify it. D9 when pure is solid. You need to increase it to high 80s to get a noticeable solid difference in its consistency.
Check this out. On the right side is thca that had some color in it(sauce/terpenes). When I decarbed it it turned to 89% D9. The one on the left side was pure glowing white thca isolate. I haven’t tested it but I’d take a guess to say it’s more pure since it’s way more solid and also a better color.
To decarb sauce/thca is really easy. Simply buy a hot plate magnetic stirrer like this one(eBay). Set it to around 150c and it will turn your extract into d9 sap.