Add support for Timestamp9 data type without time zone information about timestamp9 HOT 2 CLOSED

I don't think renaming of the existing type is going to happen. I also don't think the whole concept of timestamp is very useful, because it's stored exactly the same as a timestamptz: it's just converted to/from UTC on write/read.
Is your problem that you actually want a timestamp-like object, or do you just want to be able to provide a nanosecond timestamp text to timestamp9 conversion where you don't need to specify a timezone? For example, the following works for timestamptz: select '2023-01-01 10:00:00.100001'::timestamptz. Postgres assumes the local timezone. Timestamp9 does no such thing if you specify a nanosecond precision timestamp. This fails: select '2023-01-01 10:00:00.100000001'::timestamp9 This is something that could be implemented in the text->timestamp9 conversion. Would that solve your problem?

from timestamp9.

Yes, I think teaching timestamp9 accept select '2023-01-01 10:00:00.100000001'::timestamp9 makes sense. I'll give it a try.

from timestamp9.