The simple answer is no, for many schools you do not need any educational achievement certification in order to embark on a course. How much you are paying for that course is irrelevant. Some programmes will set a minimum educational requirement. One of the reasons for this stipulation, and the problem that is going to arise in any event, is what is the likely employer going to require?
The idea that airline recruiters are going to say "thank God we have found someone with a CPL/IR call, them for interview." is simply wishful thinking. When recruiting experienced pilots there is certainly a greater emphasis placed on their professional background than there is on their educational attainment, however, even then there is an expectation of demonstrated progression usually found on successful CV's. At the ab-initio level, that is cadets or low hour experienced pilots, there is very little else to go on other than their educational background and (where relevant) course progression, as far as the CV goes.
At this level (in fact at any level but particularly at this level,) the prospective employer is looking to eliminate anything that is (in their opinion) going to be potentially problematic. Many of the cadet programmes that set a minimum educational attainment level, do so (in part) because that is what their partners also require.
For most employers the idea that a CPL/IR will negate any requirement for an average level of educational attainment is simply wrong. There may be any number of reasons why a person doesn't complete their secondary education, but it will raise a red flag as to why they didn't subsequently rectify that deficiency.