Hi Jose,
August is a great time to head to Cocos:
www.windfinder.com/windstatistics/cocos_keeling_island?utm_source=www.windfinder.com&utm_medium=web&utm_campaign=redirect Don't expect it to be super windy, you can be unlucky and have a whole week of 10-15 knots but generally speaking you get many days of 15-20 knots. It's a bit unusual for winds to blow above 20 knots but it happens! I got really lucky in 2014 and had many days over 25 knots, but everyone told me that's very unusual.
So yeah overall I'd say expect to have 15 knot days and you won't be disappointed. I've spent a bit more than a month there and I can tell you the
wind is always gusty (at least 5 knots variations when it's light and often 10 knots variations when it's strong

), so not the quality of a proper sea breeze. That was a bit of a disappointment for me, but the scenery helps you to forget about that :)
You can hire equipment from the local kite business there, but it's expensive and in limited supply, so best to bring your own.
Definitely bring the gear you need for those conditions (10 to 20 knots). Virgin allows as many extra 23kg baggage you want for about $55 per bag if I remember correctly. Some will also bring an esky full of food (meat, veggies, etc.) as long as this food comes from WA it's all good. It's great idea since food there is about 2x more expensive than your average coles/woolies, and it's also in limited supplies.
Expect to spend a bare minimum of $150 per night for the most basic form of accommodation....accommodation is very limited so best you book ASAP
There is really only 1 kite spot and it's at the south eastern end of West island. No accommodation next to the kite spot, so it's great to have some form of transportation for the 5km drive to kite beach.
Car hire is super expensive but you can also hire mopeds and bicycles for cheaper. There will be many other kiters there so it's likely you'll be able to hitch a ride every day. Many people leave their gear at the kite beach overnight, so you don't have to carry it back and forth, locals leave their doors unlocked and keys in the ignition so you don't have to worry about getting your stuff stolen.
There are many other threads about Cocos in this forum, use the search engine or Google and you will find more info.
Have a great time, Cocos is an awesome place even for non-kiters!
Christian