missing shingles from the roof after 9 years - is it workmanship or not?

Missing shingles after 9 years doesn’t necessarily mean poor workmanship, but it certainly could be a contributing factor. Properly installed asphalt shingles should generally last considerably longer than 9 years. Shingles coming loose can result from improper nailing, incorrect nail placement, inadequate sealing, wind damage, or deterioration of the shingles themselves. As for workmanship warranties, there isn’t a universal 10-year industry standard. Most roofing contractors offer their own workmanship warranties, commonly ranging from 2 to 10 years, depending on the company and original agreement. Manufacturer warranties are separate and typically cover material defects rather than installation errors. Without the original paperwork, I wouldn’t assume a 10-year workmanship warranty applies. My recommendation would be to have the affected area inspected. An experienced roofer can often determine whether shingles were improperly fastened or whether wind damage or material failure is the more likely cause. At only 9 years old, I would definitely investigate the cause before simply replacing the missing shingles.