For £350 more you get better forks, shock, brakes, shifters (though I reckon SLX is better than X9 for the dual action, unless the new X9 has dual action as well) and the reverb. Slightly lighter cassette as well.
If money is an issue and you have enough cash for the 6, then I suggest you save a bit more for the 7.
Having said that, I was in a similar position to you last year. Remember, there could be a lead time associated with the bike as well depending on size. So you’re looking at 2-4 weeks for the bike to be assembled, a week for payment and delivery, meaning 5 weeks with no riding if you’re bikeless at present. If you add say, 4 weeks to save up the extra cash then that’s 9 weeks you’re missing out on.
Ultimately, the best bike is the one between your legs (like some other things).