One way I found it and nothing elegant was as follows.
Use the substring () function together with rand () to select a letter randomly from all of the alphabet I passed as an argument.
After that use the concat () function to concatenate all the letters into one.
delimiter $$
drop procedure if exists projBD.populaAluno $$
create procedure populaAluno()
begin
declare nome varchar(100);
declare idade int ;
declare cr float;
declare counter int default 0;
while counter <= 10000 do
set nome = concat(substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1),
substring('ABCDEFGHIJKLMNOPQRSTUVWXYZ ', rand()*28, 1)
) ;
set idade = floor(1 + (rand() * 99));
set cr = rand()*10 ;
insert into ALUNO (nome,idade,cr)
values (nome,idade,cr);
set counter = counter + 1;
end while;
End $$
delimiter ;