I crossed multiplied to get 8:9, is that correct or did I just get lucky?

To check in this one, I believe you can convert both fractions so they have the same denominator. In this case it would be 8/24 and 9/24. Greg probably has a better handle on the actual teacher speak to use here but you can ignore the 24s now that they are like terms. I guess you are effectively multiplying both sides by 24 since you are pretty much comparing two values. Either way, the ratio of 8/24 to 9/24 is definitely 8 to 9. So I would say you are correct here.

Great, thank you!