SEO Expert Developer = SEO Expert + Developer
The SEO expert is someone who has got skills to optimize your website to bring traffic and revenue. In other words, he can get more traffic from search engine
Any developer having expert skills of SEO can be called as SEO Expert Developer.
You have to hire SEO expert developer to do technical SEO to your website. He will implement all the SEO recommendation to your site
If you are running your website with WordPress then you have got plug-ins to implement SEO work and sometimes you have to do the changes to these plug-ins and configure them properly.
Ideal person to do those things is the expert SEO developer
In our team we have got several SEO experts to implement the recommendations found in the SEO audit report