DELIMITER $$
CREATE  PROCEDURE `TEST`(OUT `MyParam` VARCHAR(255) CHARSET utf8)
BEGIN  
    SET `MyParam` = 'Tritatushechki Tata';  
END$$
DELIMITER ;

CALL TEST(@MyValue);
SELECT @MyValue

Dim conn As ADODB.Connection
Dim cmd As ADODB.Command
Dim rs As ADODB.Recordset
Set conn = New ADODB.Connection
Set rs = New ADODB.Recordset
conn.ConnectionString = "DRIVER={MySQL ODBC 8.0 unicode driver};SERVER=localhost;DATABASE=db_shop;user=test;password=test;charset=utf8;Option=3;"
conn.Open
Set cmd = New ADODB.Command
cmd.ActiveConnection = conn 
cmd.CommandType = adCmdStoredProc 
cmd.CommandText = "TEST" 
cmd.Parameters.Append cmd.CreateParameter("MyParam", adVarChar, adParamOutput, 255)
'даже такой комбо не спасает -- >
Set rs = cmd.Execute("SET character_set_client='utf-8';SET character_set_results='utf-8';SET character_set_connection='utf-8'")
'<--
MsgBox rs.Fields("MyParam")
rs.Close
Set rs = Nothing
conn.Close

DELIMITER $$
CREATE PROCEDURE `ДОБАВИТЬ_ВАСЮ`(IN nameText VARCHAR(255))
BEGIN  
    INSERT INTO t_customers (customer) VALUES (nameText);
END$$
DELIMITER ;

Dim conn As ADODB.Connection
Dim cmd As ADODB.Command
Dim rs As ADODB.Recordset
Set conn = New ADODB.Connection
conn.ConnectionString = "DRIVER={MySQL ODBC 8.0 ansi driver};SERVER=localhost;DATABASE=db_shop;user=test;password=test;Option=3;"
conn.Open
Set cmd = New ADODB.Command
cmd.ActiveConnection = conn
cmd.CommandType = adCmdStoredProc 
cmd.CommandText = "ДОБАВИТЬ_ВАСЮ" 
Dim myVar As String
переменнаяВася="ВАСЯ"
cmd.Parameters.Append cmd.CreateParameter("nameText", adVarChar, adParamInput, 255, переменнаяВася)
cmd.Execute
conn.Close