When install SNO+worker via ZTP, worker node was not installed with the same OS as SNO node. 

$ oc get agent -A
NAMESPACE   NAME                                   CLUSTER    APPROVED   ROLE     STAGE
worker-1    1dac0811-6194-ea9b-a721-ad972279dcc6   worker-1   true       worker   Rebooting
worker-1    58411dcc-0b69-290b-07a0-cbb1392a4e1e   worker-1   true       master   Done


# on SNO node: 
[core@worker-1 ~]$ last reboot
reboot   system boot  5.14.0-285.el9.x Tue Mar 21 20:14   still running
reboot   system boot  5.14.0-285.el9.x Tue Mar 21 19:26 - 20:12  (00:45)
reboot   system boot  4.18.0-372.41.1. Tue Mar 21 19:22 - 19:24  (00:01)wtmp begins Tue Mar 21 19:22:48 2023
[core@worker-1 ~]$ cat /etc/redhat-release 
CentOS Stream CoreOS release 4.13


# on Worker node: 
[core@worker-0 ~]$ last reboot
reboot   system boot  4.18.0-372.41.1. Tue Mar 21 20:56   still runningwtmp begins Tue Mar 21 20:56:07 2023
[core@worker-0 ~]$ uname -r
4.18.0-372.41.1.el8_6.x86_64
[core@worker-0 ~]$ cat /etc/redhat-release 
Red Hat Enterprise Linux CoreOS release 4.13

4.13 rc.0

100%

1. Install SNO via ZTP
2. Add a worker via ZTP
3.

- agent stuck at Rebooting for worker node
- worker node has a 8.6 based RHCOS installed while SNO is on 9.2 based  CentOS Stream CoreOS

- worker expansion succeeded