I used to try to burn to DVD-9 several years ago at the height of the DVD craze, before BluRays were invented. I bought three different brands, including TDK and Verbatim iirc. 60% of them failed miserably, costing a tremendous amount of wasted time and money. I would be highly skeptical that you will have success burning to DVD-9s now that DVDs are much less popular. If you're just going to store the VOBs on flash, that's ok.