Is this due to drought?
I doubt it. Looks like nimblewill or bentgrass - cant be certain which from the pic. My north yard looked identical to this in fall. I took a thatching rake to clear the long threads off in the areas of the lawn I wanted to keep so my good stuff could fill in and turned the majority of the rest into a flower bed. I still have a few small patches that look identical to yours. Personally, easier to wait until active growth and roundup plus seed than to wage a long term control. Keep in mind autumn is the best time to seed but you could still do it in zone 9 in spring with decent results and pissible need for overseed in fall. Thats what ill be doing next month - saving my tenacity for better things >:)
Sorry for spam forgot to mention tenacity will work on either of them - but is pricey - good stuff though!. If nimblewill, could be soil issues to correct. Can you provide more info on its behavior last summer, fall, winter?
i wish you would have said yes