You don't need a PPL to sit the ATPL exams. The exams can be downward credited for CPL, PPL and LAPL. You'll need a PPL to start a modular CPL course.
If you're really wanting to get a CPL, don't bother with 9 PPL exams. Just take the ATPLs first which is, let's face it, the hardest and biggest hurdle.