Hi Nitin,
1. Which PI certification should I opt. I guess there is development associate and professional level.
We should have minimum 6 months of hands on experience on the version which we are applying for certification.
After registering to www.sapindiacertification.com you should check the eligibility for associate and professional
As shown in the below screenshot, please click on each link to know the eligibility criteria for the certification.
At present we have certifications for SAP PI 7.1 / 7.11/ 7.3 / 7.31 [Associate and Professional].
For Associate / Professional certifications we should have minimum 3 to 5 yrs of experience in SAP PI.
2. How to prepare to score good. Work experience and cracking exam questions seem to be different.
Please go through the below link for certification / Syllabus / Topic areas /cut off score and sample questions.
Syllabus for SPA PI 7.3 certification
Syllabus for SPA PI 7.31 certification
3. Is it correct that to apply for certification directly one need to be spend at least one year in the current company or I can apply immediately if I can take an certificate or something from my current or previous company that I have worked in some SAP PI projects.
You can only apply through your current organization only and you should have min 6 months of experience in the version which your are applying for.
4. How to book a seat and complete the payment.
you have to register in "www.sapindiacertification.com" and upload your profile.
Then your profile will be verified and approved by the SAP team and you will get a confirmation mail and guidelines for further process to your register mail id.
--> upload the consent form
--> NOC from HR / Practice lead
--> Payment details etc.
--> select the examination date.
Please refer the below links for more information
How to Approach and Pass a SAP Certification
Regards
Bhargava Krishna