If I lived in CA 3 months, earned wages from a CA company only while living in TX,

1.)  If your California income is more than the amount shown in any of the tables below, you need to file a tax return. (This would include interest, and the 1099-B)

The lowest number is Under 65  $18,496.  To see the full tables are Part-year resident and nonresident | FTB.ca.gov. 

If you do need to allocate the Interest and 1099-B it would be based on when you received the interest, and when you sold the securities.

2.)  If you lived in Texas, worked in Texas, but worked for a California based company.  You do not have to file a California tax return.

3.)  Since Texas does not have an Income Tax you do not have to file a Texas tax return.