My thoughts on this are simple: You can buy any Elite with credits anytime, as long as you are high enough level. You can buy them for credits but you need to be at least level 10 to get even just the Tier 5 Elites. Here are the statistics.
Must be LvL 10 to buy Tier 5 elites
Must be LvL 15 to buy Tier 6 elites
Must be LvL 20 to buy Tier 7 elites
Must be LvL 25 to buy Tier 8 elites
Must be LvL 30 to buy Tier 9 elites
Each of them have different prices, so here is my re-balance of their prices.
Tier 5 is 75 Credits
Tier 6 is 90 Credits
Tier 7 is 100 Credits
Tier 8 is 115 Credits
Tier 9 is 120 Credits
I really hope this gets added, I love this game a lot, and think this would be an epic re-balance for Elites! (Also, while you are at it, can you add the ability to place and make flags?)