https://github.com/arekinath/PivApplet
Here's the full sequence for both slots:
Slot 9a (PIV Authentication):
yubico-piv-tool -r 'OMNIKEY AG Smart Card Reader USB' -a generate -s 9a --pin=123456 --key=010203040506070801020304050607080102030405060708 > pubkey-9a.pem
yubico-piv-tool -r 'OMNIKEY AG Smart Card Reader USB' -a verify-pin -a selfsign-certificate -s 9a -S '/CN=PIV/' --pin=123456 --key=010203040506070801020304050607080102030405060708 < pubkey-9a.pem > cert-9a.pem
yubico-piv-tool -r 'OMNIKEY AG Smart Card Reader USB' -a import-certificate -s 9a --key=010203040506070801020304050607080102030405060708 < cert-9a.pem