Apex domains cannot have CNAME records.
Question and response
Question
dig oraclecloud9.com. NS
Answer
oraclecloud9.com. 2 NS ns3.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns6.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns7.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns2.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns4.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns5.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
oraclecloud9.com. 2 NS ns1.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com.
Authority
The response has no authority records.
Additional
ns1.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com. 2 A 151.104.143.132
ns2.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com. 2 A 151.104.140.135
ns3.p200.dns.me-dcc-muscat-1.oci.oraclerealm9.com. 2 A 151.104.141.103
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0