With all the job-hopping that has been going on with my own FH lately (cue eye-roll here), I can sympathize, as we've been trying to plan a holiday in September for ages.
Basically, when he gets hired, they should asked him if he's got anything ALREADY booked. If it's on paper, paid for, etc, then there's really nothing they can do about it. His time off might not be paid, seeing as it's happening so soon after hiring, but at the end of the day, so long as he's up front with the information (either literally just after he gets the job offer or on his first day of work), then there's nothing they can do.
So what I advise is booking your honeymoon for whenever you please, because by the time he gets that job, it will be virtually set in stone. If a company wants to hire him in the first place, I doubt he'd lose the position so long as he discloses the information straight away.
The past 3 employers my FH has gone through have all acted the same way - he told them he had something booked in September & even though that's technically before he's contractually allowed to take holiday time (before probationary period is up), they told him that since it's already booked, there's nothing they can do to stop him from taking time off.
Basically, by pre-booking it, you're not giving the employer a choice - and you get your holiday! I'm sure most normal people won't mind, given that it's a wedding & honeymoon, not just any old holiday!!