Not in 9i, but in 10g - we can get some of them.

I've chopped out ones I didn't feel relevant (like log_archive* things) from the following, but this shows what you could expect to see in 10g, <<<<====== indicates you "can" see this parameter from another session:

ops$tkyte@ORA10GR2> select a.name,
2 case when b.name is not null then '<<<<=====' end,
3 a.description
4 from ( select name , description
5 from v$parameter
6 where isses_modifiable = 'TRUE' ) a,
7 ( select distinct name
8 from v$ses_optimizer_env ) b
9 where a.name = b.name (+);

NAME CASEWHENB DESCRIPTION
------------------------------ --------- ------------------------------
tracefile_identifier trace file custom identifier
timed_statistics maintain internal timing stati
stics

timed_os_statistics internal os statistic gatherin
g interval in seconds

nls_language NLS language name
nls_territory NLS territory name
nls_sort NLS linguistic definition name
nls_date_language NLS date language name
nls_date_format NLS Oracle date format
nls_currency NLS local currency symbol
nls_numeric_characters NLS numeric characters
nls_iso_currency NLS ISO currency territory nam
e

nls_calendar NLS calendar system name
nls_time_format time format
nls_timestamp_format time stamp format
nls_time_tz_format time with timezone format
nls_timestamp_tz_format timestampe with timezone forma
t

nls_dual_currency Dual currency symbol
nls_comp NLS comparison
nls_length_semantics create columns using byte or c
har semantics by default

nls_nchar_conv_excp NLS raise an exception instead
of allowing implicit conversi
on


db_file_multiblock_read_count db block to be read each IO

ddl_wait_for_locks Disable NOWAIT DML lock acquis
itions

resumable_timeout set resumable_timeout
db_block_checking header checking and data and i
ndex block checking

recyclebin recyclebin processing
create_stored_outlines create stored outlines for DML
statements

global_names enforce that database links ha
ve same name as remote databas
e

session_cached_cursors Number of cursors to cache in
a session.

parallel_min_percent minimum percent of threads req
uired for parallel query

cursor_sharing <<<<===== cursor sharing mode
parallel_instance_group instance group to use for all
parallel operations

hash_area_size <<<<===== size of in-memory hash work ar
ea

max_dump_file_size Maximum size (blocks) of dump
file

object_cache_optimal_size optimal size of the user sessi
on's object cache in bytes

object_cache_max_size_percent percentage of maximum size ove
r optimal of the user session'
s object cache

commit_write transaction commit log write b
ehaviour

optimizer_features_enable <<<<===== optimizer plan compatibility p
arameter

sort_area_size <<<<===== size of in-memory sort work ar
ea

sort_area_retained_size <<<<===== size of in-memory sort work ar
ea retained between fetch call
s

sql_trace enable SQL trace
optimizer_mode <<<<===== optimizer mode
star_transformation_enabled <<<<===== enable the use of star transfo
rmation

optimizer_index_cost_adj <<<<===== optimizer index cost adjustmen
t

optimizer_index_caching <<<<===== optimizer percent index cachin
g

query_rewrite_enabled <<<<===== allow rewrite of queries using
materialized views if enabled

query_rewrite_integrity <<<<===== perform rewrite using material
ized views with desired integr
ity

sql_version sql language version parameter
for compatibility issues

workarea_size_policy <<<<===== policy used to size SQL workin
g areas (MANUAL/AUTO)

optimizer_dynamic_sampling <<<<===== optimizer dynamic sampling
statistics_level <<<<===== statistics level
skip_unusable_indexes <<<<===== skip unusable indexes if set t
o TRUE

olap_page_pool_size size of the olap page pool in
bytes

asm_power_limit number of processes for disk r
ebalancing

sqltune_category Category qualifier for applyin
g hintsets


91 rows selected.