Hope you are doing well. A Google AdSense ID gives you a set of codes for different kinds of ads. This code can be used at any number of sites and blogs. You should make sure that you use it on legible sites, and you writing content which is original. Also, the website should not be filled with scrap content and empty pages.
Thus you do not need to apply for a new AdSense ID, nor would Google allow you to have multiple AdSense IDs under the same name and address. Under the same AdSense ID, you can track earning from different websites as well. Make use of the detailed reporting facilities given by Google AdSense.
The waiting time when you were initially applying for Google AdSense is 6 months. But now that you already have the ID, you can apply it to any site at any point of time. Over here, in IndiaStudyChannel, we will want you to be at least a Gold level member before you attach your AdSense ID.
ISC, will present a specially created profile page to Google AdSense. From here, Google AdSense can monitor your profile on ISC. They will look for whether you are having at least some good content on which their Ads are being shown. They will want to look into whether your content is authoritative. They will check if you are copy pasting or posting scrap content.
If any of such malpractices are observed by Google AdSense, they will send an email to your directly, informing to remove your AdSense from your content.
Similarly, ISC will want you to post quality content for which the Editors team is present to guide you along the way.
I would suggest that you post at least 10 to 15 articles in ISC, have a good contribution in Forum and Ask Experts section and gain a Gold level membership. This will increase the quality of your profile on ISC. Infact Google AdSense will thus love to have their Ads put up on your write ups.
I hope this helps.
Self-discipline brings success; but restraints too binding bring self-defeat.