Do not go into a job with the thought that you may rightly treat management as children, using redirection and manipulation to bring them along, however much you may know better. Whether they are fools or not, if you take their money they obtain the right to be treated as adults.

Doesn't mean don't take the job, but 'covert' and 'ninja' raise my hackles. It makes it sound like your employer is the enemy.

If you can do a good enough job with PHP you may gain enough credibility to convince them. Or not. Good luck deciding.