Depends on your roles & responsibilities in that job role. Ignore that 'experience as a....required' line as that is not a mandatory requirement.
If you can get a reference letter for your 2006-09 stint which shows your responsibilities to be similar to main duties under NOC 2171, then you can choose that NOC. Period.
In fact, you can get away with NOT declaring that work experience. Your CRS is already maxed with your current job as you have more than 3 years of experience.
If your primary NOC is 2171, you will get only 13 points for Experience on FSWP scale. If those are good enough for you to hit 67/100, feel free to remove thart 2006-0 experience from your work history because it adds nothing to your profile. Only mention it in Personal history post ITA.
And before you ask, this isn't misrepresentation. This is just partial disclosure and CIC is fine with you declaring only what you need points for in your profile.
Hope that clarifies. All the best!