Questions about buying items with credits from website

I wanted to buy some credit points and use it to purchase a good sets and other accessories. I saw the online Add Items page and I liked some of the armors but it says this on each armor. "Available for Soldier, Rank 1 / Soldier, Rank 1 or higher". I have very low Abyss points (like 5 points only) so am I able to equip those items or not?

Another thing is do you guys recommend me to purchase items from the website like that or from others users in the game who sell them? Trying to find the strongest one so which one should I go for?

 

You won't be able to wear the items that requires Rank1 if you are Rank2 or lower.
Buy stuff from the Black Cloud Trader Shop, it's more safer.
The strongest set is HAC.