I've just bought domain from auction but it'll take few days for transfer, so can I start creating website with wordpress.org and later link a domain to it?
Link to your own site or an existing free blog from Wordpress.com? Wordpress hard codes the URL in the database so if you develop with a different domain you will have to change all the URLs in the posts table. There are other options when you are more clear on your intent.
wordpress.com is good also you can check a free hosting and you can mapped the domain later with free hosting..
if you buy the hosting they will provide you temp URL for accessing until the URL make live. If you have already a hosting/domain then you can create subdomain and create your site once you have domain ready you can add as addon with same folder so it can work... Just need to update url from the table wp_options