I was talking to a controller and was receiving vectors to an ILS and I noticed that the radio was getting hard to get a word in due to traffic so one time I was giving a heading to turn 090 however instead of repeating 090 I stated east over the radio along with my abbreviated call sign to shorten radio traffic is this ok?
No. Please don't do this. I appreciate that you're trying to save time, but two problems:
1. The difference between "south" and "zero niner zero" is two words. If I don't have the ~1 second that takes, I'm not going to give you the instruction anyway. We're accounting for slow and erroneous readbacks (not that we want them to happen, of course).
2. "South" is not the instruction. That could be interpreted as anything between 135 to 225 degrees, maybe more. Especially when vectoring for an approach or for traffic, exact headings are necessary. Generally, cardinal directions are only given when that kind of precision isn't needed.
Thanks for trying to look out for us, but read back the instruction you're given so we're all on the same page.