Chun In-Gee of South Korea fired a seven-under 65 for fourth place and Thailand star Ariya Jutanugarn is also still in the hunt after shooting a 70 take sole possession of fifth.
A 71-minute rain delay meant a second straight day with weather interruption and it also lead to the second round not being completed. Kerr posted a 62 to tie the course record after playing the back nine in 29, including birdies on seven of the last eight holes.
Jang was also nine-under when darkness fell, but her birdie Friday at the par-three eighth, the penultimate hole of her round, gave her sole possession of the lead.
If Jang were to win, she'd be the first sponsor's invite to win an event since Lydia Ko at the CP Canadian Women's Open in 2013.
Among those another shot back were second-ranked So Yeon Ryu (69), coming off a victory in the major ANA Inspiration, and Olympic champion Inbee Park.
Australia's top-ranked female player Minjee Lee returns to the scene of one of her three LPGA Tour triumphs when the tour moves to Hawaii this week.
Ko said she is unfazed by talk around her ranking - she acknowledges the talent on course but just wants to continue to improve her own game. Lee had a mixed round with five birdies, four bogies and a double bogey to shoot one-over, dropping 20 spots back to a share of 25th at four-under for the tournament. "I hit it fine". She was just one back after sinking a 15-footer from the fringe on the 16th. The two-time LPGA Player of the Year is winless in her last 69 starts.
"We talked about how many times I won conventional and how many times have I won left-hand-low and the difference was astronomical".
Hometown favorite Michelle Wie, the 2014 champion of the event, is eight shots behind following an even-par 72.
"Because I had to finish up the second round this morning and play another 18 I was a little bit exhausted", she said through an interpreter. I had a couple of good days of rest and I'm ready for the week to start.
Lewis birdied four of her first five holes to get to 8 under early.