Hi n00k!e, welcome to Bitcoin.
a) The main catch is that there's no guarantee the exchange rate will indeed rise. There could very well be a bubble about to burst any moment. Most people here expect rates to rise, though.
b) The rates people are willing to pay. If you are willing to pay $9.5/BTC and nobody else is currently, you will raise the exchange rate (of course, you'll have to make a large purchase for you personally to affect it significantly).
c) You might be misunderstanding that speculating is not what Bitcoin is about. Sure, you can do that, and you may make a profit. But Bitcoin aspires to be a medium of exchange to buy goods and services which is superior to currently existing currencies and wealth store/transfer services.