I did it this way: (only for wind necklace, im the biggest cheapskate in the history of GC)
1. go to a low-populated server
2. buy whatever amount of gems that you want
3. whenever elena shows up, press the enter key like crazy once the glow on her staff expands
4. just repeat the process until you reach +9
take note: while im upgrading the most troublesome characters that took time to get it to +9 were arme and ryan, nakailang wind necky ako sa kanila.
oh one more thing, nung naacquire ko agad cna amy at jin, napansin ko na dire-diretso yung upgrade, puro success no fails.