will i be eligible to get VCP certification without getting required training courses at an authorized commercial training center as iam doing learning from VCP CBT.
on one web its mentioned that " learners must attend an official VMware course in order to be authorized to sit for an exam "
No you will not.
Each VCP has a dedicated page where you can review the requirements - including the training, see here for an example: VMware Certified Professional 6.5 - Data Center Virtualization (VCP6.5-DCV)
The only exception is for holders of certain Cisco certifications - there is a path for the VCP6-NV which does not require training, you'll find that here: VMware Certified Professional 6 – Network Virtualization (VCP6-NV)