Okay.
Reading the MRF89XAM9A datasheet on page 7 "1.3.5 VCO TANK TRIM VALUE", it says you need to set VCOT<1:0> = ‘01’.
From Datasheet:
1.3.5 VCO TANK TRIM VALUE
The VCO Trim bits (VCOT<1:0>) in the
GCONREG<2:1> should be set for VCOT<1:0> = ‘01’
for the inductor values of the module.

That would change MC's value of Register 00 from $2E to $2A, and your value of Register 00 from $28 to $2A.

That might explain why the PLL won't lock.