Help with a sub yarn

Merry Christmas everyone! Its been awhile since I’ve been on KH–busy at my job. This time last year I was hoping for a Christmas miracle (a job).
So, my dilemma is this. The knitted hat pattern I want to use calls for chunky yarn. Pattern calls for CO 66 stitches with size 11 needles. I don’t have chunky yarn. What I have is red heart worsted weight using size 8. Please help and suggestions are welcomed. The hat has to be completed by Friday for a Christmas present. Thanks everyone.

What measurement does the 66 stitches work out to? Cast on the number that will measure the same in size 8 or 9 needles on your worsted. If there’s ribbing it has to be an even number for 1x1 rib, if it’s 2x2 rib it needs to be a multiple of 4. Then more or less follow the pattern. If you have something like 80 or 90 sts, then start the decreases at k8, k2tog, knit a round plain, then k7, k2tog, and knit one plain. Continue like this until you’re down to about 3 sts between decs then dec on every round until you have about 12-16 sts and pull the tail through them to finish.