Size will vary...

"Size will vary based on hook size, materials and crochet style."

When you see this line, does it mean anything to you?

I can't stress how much this is true. 

I get pictures and messages sent to me all the time of how their item came out much bigger than what is indicated on the pattern. To the point that I might need to add to all the patterns that I crochet very tight (but I don't feel that I do) cause my 9 inch item seems to be most peoples 11 inch item. Even if you used exactly the same yarn, exactly the same hook size, your style of crochet may be a lot looser than mine. I have even had my testers who use smaller hooks come out with larger results. I have to say sometimes it baffles me how but of course I know just one factor can change the results. 

The best I can do is give a gauge to follow. If you want the item to be as close to the size indicated, then following the gauge is your best option. To do this you may need to adjust your hook size to accommodate the materials your using and/or your personal crochet style.